evaluation for the semantic search

## Summary of the Pull Request

This PR fixes the settings UI for the top-level command alias.



<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist


https://github.com/user-attachments/assets/0d1e1392-0293-4482-97cb-e8e8c0ed0dd5


- [x] Closes: #41301
<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

.claude/CLAUDE.md

@@ -0,0 +1 @@
+../.github/copilot-instructions.md

.claude/agents

@@ -0,0 +1 @@
+../.github/agents

.claude/commands

@@ -0,0 +1 @@
+../.github/prompts

.claude/rules

@@ -0,0 +1 @@
+../.github/instructions

.claude/skills

@@ -0,0 +1 @@
+../.github/skills

.github/actions/spell-check/allow/zoomit.txt

@@ -0,0 +1,63 @@
+acq
+APPLYTOSUBMENUS
+AUDCLNT
+bitmaps
+BUFFERFLAGS
+centiseconds
+Ctl
+CTLCOLOR
+CTLCOLORBTN
+CTLCOLORDLG
+CTLCOLOREDIT
+CTLCOLORLISTBOX
+CTrim
+DFCS
+dlg
+dlu
+DONTCARE
+DRAWITEM
+DRAWITEMSTRUCT
+DWLP
+EDITCONTROL
+ENABLEHOOK
+FDE
+GETCHANNELRECT
+GETCHECK
+GETTHUMBRECT
+GIFs
+HTBOTTOMRIGHT
+HTHEME
+KSDATAFORMAT
+LEFTNOWORDWRAP
+letterbox
+lld
+logfont
+lround
+MENUINFO
+mic
+MMRESULT
+OWNERDRAW
+PBGRA
+pfdc
+playhead
+pwfx
+quantums
+REFKNOWNFOLDERID
+reposted
+SCROLLSIZEGRIP
+SETDEFID
+SETRECT
+SHAREMODE
+SHAREVIOLATION
+STREAMFLAGS
+submix
+tci
+TEXTMETRIC
+tme
+TRACKMOUSEEVENT
+Unadvise
+WASAPI
+WAVEFORMATEX
+WAVEFORMATEXTENSIBLE
+wil
+WMU

.github/actions/spell-check/excludes.txt

@@ -101,6 +101,7 @@
 ^doc/devdocs/akaLinks\.md$
 ^NOTICE\.md$
 ^src/common/CalculatorEngineCommon/exprtk\.hpp$
+^src/common/UnitTests-CommonUtils/
 ^src/common/ManagedCommon/ColorFormatHelper\.cs$
 ^src/common/notifications/BackgroundActivatorDLL/cpp\.hint$
 ^src/common/sysinternals/Eula/

.github/actions/spell-check/expect.txt

@@ -11,6 +11,7 @@ ACCESSDENIED
 ACCESSTOKEN
 acfs
 ACIE
+ACR
 AClient
 AColumn
 acrt
@@ -44,6 +45,7 @@ ALLCHILDREN
 ALLINPUT
 Allman
 Allmodule
+ALLNOISE
 ALLOWUNDO
 ALLVIEW
 ALPHATYPE
@@ -57,7 +59,6 @@ AOC
 aocfnapldcnfbofgmbbllojgocaelgdd
 AOklab
 aot
-APARTMENTTHREADED
 APeriod
 apicontract
 apidl
@@ -95,6 +96,7 @@ asf
 Ashcraft
 AShortcut
 ASingle
+ASUS
 ASSOCCHANGED
 ASSOCF
 ASSOCSTR
@@ -104,6 +106,7 @@ atl
 ATRIOX
 aumid
 authenticode
+AUO
 AUTOBUDDY
 AUTOCHECKBOX
 AUTOHIDE
@@ -121,6 +124,10 @@ azureaiinference
 azureinference
 azureopenai
 backticks
+Backlight
+Badflags
+Badmode
+Badparam
 bbwe
 BCIE
 bck
@@ -129,6 +136,7 @@ bezelled
 bhid
 BIF
 bigbar
+BIGGERSIZEOK
 bigobj
 binlog
 binres
@@ -193,6 +201,7 @@ Carlseibert
 CAtl
 caub
 CBN
+Cds
 cch
 CCHDEVICENAME
 CCHFORMNAME
@@ -212,6 +221,7 @@ checkmarks
 CHILDACTIVATE
 CHILDWINDOW
 CHOOSEFONT
+Chunghwa
 CIBUILD
 cidl
 CIELCh
@@ -226,7 +236,7 @@ claude
 CLEARTYPE
 clickable
 clickonce
-CLIENTEDGE
+clientedge
 clientid
 clientside
 CLIPBOARDUPDATE
@@ -238,6 +248,7 @@ CLSCTX
 clsids
 Clusion
 cmder
+CMN
 CMDNOTFOUNDMODULEINTERFACE
 cmdpal
 CMIC
@@ -292,6 +303,7 @@ Corpor
 cotaskmem
 COULDNOT
 countof
+Cowait
 covrun
 cpcontrols
 cph
@@ -310,11 +322,14 @@ CRECT
 CRH
 critsec
 cropandlock
+crt
+CROPTOSQUARE
 Crossdevice
 csdevkit
 CSearch
 CSettings
 cso
+CSOT
 CSRW
 CStyle
 cswin
@@ -357,11 +372,14 @@ DBPROPIDSET
 DBPROPSET
 DBT
 DCBA
+DCapabilities
 DCOM
 DComposition
 DCR
+ddc
 DDEIf
 Deact
+debouncer
 debugbreak
 decryptor
 Dedup
@@ -379,6 +397,7 @@ DEFAULTTOPRIMARY
 DEFERERASE
 DEFPUSHBUTTON
 deinitialization
+DELA
 DELETEDKEYIMAGE
 DELETESCANS
 DEMOTYPE
@@ -413,18 +432,20 @@ DISABLEASACTIONKEY
 DISABLENOSCROLL
 diskmgmt
 DISPLAYCHANGE
-DISPLAYCONFIG
+displayconfig
 DISPLAYFLAGS
 DISPLAYFREQUENCY
 displayname
 DISPLAYORIENTATION
+diu
 divyan
 Dlg
 DLGFRAME
-DLGMODALFRAME
+dlgmodalframe
 dlib
 dllhost
 dllmain
+Dmdo
 DNLEN
 DONOTROUND
 DONTVALIDATEPATH
@@ -434,6 +455,7 @@ downsampling
 downscale
 DPICHANGED
 DPIs
+DPMS
 DPSAPI
 DQTAT
 DQTYPE
@@ -471,15 +493,19 @@ DWMWINDOWMAXIMIZEDCHANGE
 DWORDLONG
 dworigin
 dwrite
+Dxva
 dxgi
 eab
+EAccess
 easeofaccess
 ecount
-Edid
+edid
 EDITKEYBOARD
 EDITSHORTCUTS
 EDITTEXT
 EFile
+EInvalid
+eep
 eku
 emojis
 ENABLEDELAYEDEXPANSION
@@ -489,14 +515,15 @@ ENABLETEMPLATE
 encodedlaunch
 encryptor
 ENDSESSION
+ENot
 ENSUREVISIBLE
 ENTERSIZEMOVE
 ENTRYW
 ENU
 environmentvariables
-EOAC
 EPO
 epu
+EProvider
 ERASEBKGND
 EREOF
 EResize
@@ -550,6 +577,7 @@ fdx
 FErase
 fesf
 FFFF
+FFh
 Figma
 FILEEXPLORER
 fileexploreraddons
@@ -592,6 +620,7 @@ formatetc
 FORPARSING
 foundrylocal
 FRAMECHANGED
+Framechanged
 FRestore
 frm
 FROMTOUCH
@@ -653,6 +682,8 @@ gwl
 GWLP
 GWLSTYLE
 hangeul
+Hann
+Hantai
 Hanzi
 Hardlines
 hardlinks
@@ -711,6 +742,7 @@ HKPD
 HKU
 HMD
 hmenu
+HMON
 hmodule
 hmonitor
 homies
@@ -728,6 +760,7 @@ hotkeys
 hotlight
 hotspot
 HPAINTBUFFER
+HPhysical
 HRAWINPUT
 hredraw
 hres
@@ -738,6 +771,7 @@ hsb
 HSCROLL
 hsi
 HSpeed
+HSync
 HTCLIENT
 hthumbnail
 HTOUCHINPUT
@@ -747,6 +781,7 @@ HVal
 HValue
 Hvci
 hwb
+HWP
 HWHEEL
 HWINEVENTHOOK
 hwnd
@@ -760,6 +795,7 @@ IAI
 icf
 ICONERROR
 ICONLOCATION
+ICONONLY
 IDCANCEL
 IDD
 idk
@@ -803,6 +839,7 @@ INITTOLOGFONTSTRUCT
 INLINEPREFIX
 inlines
 Inno
+Innolux
 INPC
 inproc
 INPUTHARDWARE
@@ -844,6 +881,7 @@ istep
 ith
 ITHUMBNAIL
 IUI
+IVO
 IUWP
 IWIC
 jeli
@@ -857,6 +895,7 @@ jpnime
 Jsons
 jsonval
 jxr
+Kantai
 keybd
 KEYBDDATA
 KEYBDINPUT
@@ -878,6 +917,7 @@ KILLFOCUS
 killrunner
 kmph
 kvp
+KVM
 Kybd
 LARGEICON
 lastcodeanalysissucceeded
@@ -899,6 +939,9 @@ LEFTTEXT
 LError
 LEVELID
 LExit
+Lenovo
+LGD
+LFU
 lhwnd
 LIBFUZZER
 LIBID
@@ -1003,6 +1046,7 @@ MAPTOSAMESHORTCUT
 MAPVK
 MARKDOWNPREVIEWHANDLERCPP
 MAXIMIZEBOX
+Maximizebox
 MAXSHORTCUTSIZE
 maxversiontested
 mber
@@ -1015,6 +1059,7 @@ MDL
 mdtext
 mdtxt
 mdwn
+mccs
 meme
 memicmp
 MENUITEMINFO
@@ -1024,9 +1069,7 @@ MERGEPAINT
 Metacharacter
 metadatamatters
 Metadatas
-Metacharacter
 metafile
-Metacharacter
 mfc
 Mgmt
 Microwaved
@@ -1038,6 +1081,7 @@ mikeclayton
 mindaro
 Minimizable
 MINIMIZEBOX
+Minimizebox
 MINIMIZEEND
 MINIMIZESTART
 MINMAXINFO
@@ -1074,6 +1118,7 @@ MOVESIZEEND
 MOVESIZESTART
 MRM
 Mrt
+mrt
 mru
 MSAL
 msc
@@ -1099,6 +1144,7 @@ Mso
 msrc
 msstore
 mstsc
+mswhql
 msvcp
 MT
 MTND
@@ -1116,6 +1162,7 @@ MYICON
 myorg
 myrepo
 NAMECHANGE
+Nanjing
 namespaceanddescendants
 nao
 NCACTIVATE
@@ -1184,6 +1231,7 @@ NOMCX
 NOMINMAX
 NOMIRRORBITMAP
 NOMOVE
+Nomove
 NONANTIALIASED
 nonclient
 NONCLIENTMETRICSW
@@ -1205,6 +1253,7 @@ NORMALUSER
 NOSEARCH
 NOSENDCHANGING
 NOSIZE
+Nosize
 NOTHOUSANDS
 NOTICKS
 NOTIFICATIONSDLL
@@ -1212,9 +1261,11 @@ NOTIFYICONDATA
 NOTIFYICONDATAW
 NOTIMPL
 NOTOPMOST
+Notopmost
 NOTRACK
 NOTSRCCOPY
 NOTSRCERASE
+Notupdated
 notwindows
 NOTXORPEN
 nowarn
@@ -1258,6 +1309,7 @@ opensource
 openurl
 openxmlformats
 OPTIMIZEFORINVOKE
+Optronics
 ORPHANEDDIALOGTITLE
 ORSCANS
 oss
@@ -1293,6 +1345,7 @@ PATINVERT
 PATPAINT
 pbc
 pbi
+PBP
 PBlob
 pbrush
 pcb
@@ -1307,6 +1360,7 @@ PDBs
 PDEVMODE
 pdisp
 PDLL
+pdmodels
 pdo
 pdto
 pdtobj
@@ -1329,6 +1383,7 @@ pguid
 phbm
 phbmp
 phicon
+PHL
 Photoshop
 phwnd
 pici
@@ -1361,6 +1416,8 @@ Popups
 POPUPWINDOW
 POSITIONITEM
 POWERBROADCAST
+powerdisplay
+POWERDISPLAYMODULEINTERFACE
 POWERRENAMECONTEXTMENU
 powerrenameinput
 POWERRENAMETEST
@@ -1415,6 +1472,7 @@ projectname
 PROPERTYKEY
 Propset
 PROPVARIANT
+prot
 PRTL
 prvpane
 psapi
@@ -1442,12 +1500,16 @@ PTOKEN
 PToy
 ptstr
 pui
+pvct
 PWAs
 pwcs
 PWSTR
 pwsz
 pwtd
+Qdc
 QDC
+qdc
+QDS
 qit
 QITAB
 QITABENT
@@ -1670,6 +1732,7 @@ sigdn
 Signedness
 SIGNINGSCENARIO
 signtool
+SIIGBF
 SINGLEKEY
 sipolicy
 SIZEBOX
@@ -1734,6 +1797,7 @@ STARTUPINFOW
 startupscreen
 STATFLAG
 STATICEDGE
+Staticedge
 staticmethod
 STATSTG
 stdafx
@@ -1770,6 +1834,7 @@ subkeys
 sublang
 SUBMODULEUPDATE
 subresource
+swp
 Superbar
 sut
 svchost
@@ -1778,7 +1843,8 @@ SVGIO
 svgz
 SVSI
 SWFO
-swp
+SWP
+Swp
 SWPNOSIZE
 SWPNOZORDER
 SWRESTORE
@@ -1838,7 +1904,9 @@ THEMECHANGED
 themeresources
 THH
 THICKFRAME
+Thickframe
 THISCOMPONENT
+Tianma
 throughs
 TILEDWINDOW
 TILLSON
@@ -1919,13 +1987,13 @@ UNLEN
 UNORM
 unremapped
 Unsubscribes
+unsubscribes
 unvirtualized
 unwide
 unzoom
 UOffset
 UOI
 UPDATENOW
-UPDATEREGISTRY
 updown
 UPGRADINGPRODUCTCODE
 upscaling
@@ -1952,6 +2020,8 @@ vcamp
 vcenter
 vcgtq
 VCINSTALLDIR
+vcp
+vcpname
 Vcpkg
 VCRT
 vcruntime
@@ -1964,6 +2034,8 @@ VERIFYCONTEXT
 VERSIONINFO
 VERTRES
 VERTSIZE
+VESA
+vesa
 VFT
 vget
 vgetq
@@ -1995,6 +2067,7 @@ VSM
 vso
 vsonline
 VSpeed
+VSync
 vstemplate
 vstest
 VSTHRD
@@ -2036,7 +2109,7 @@ winapi
 winappsdk
 windir
 WINDOWCREATED
-WINDOWEDGE
+windowedge
 WINDOWINFO
 WINDOWNAME
 WINDOWPLACEMENT
@@ -2060,12 +2133,12 @@ WINL
 winlogon
 winmd
 winml
-WINNT
 winres
 winrt
 winsdk
 winsta
 WINTHRESHOLD
+WINNT
 WINVER
 winxamlmanager
 withinrafael
@@ -2077,6 +2150,7 @@ WKSG
 Wlkr
 wmain
 Wman
+wmi
 WMI
 WMICIM
 wmimgmt
@@ -2089,6 +2163,7 @@ WNDCLASSEX
 WNDCLASSEXW
 WNDCLASSW
 WNDPROC
+Wndproc
 wnode
 wom
 WORKSPACESEDITOR
@@ -2174,4 +2249,4 @@ Zoneszonabletester
 Zoomin
 zoomit
 ZOOMITX
-Zorder
+Zorder

.github/actions/spell-check/patterns.txt

@@ -274,5 +274,18 @@ St&yle
 # 0x6f677548 is user name but user folder causes a flag
 \bx6f677548\b
 
+# Windows API constants and hardware interface terms
+\bCOINIT[_A-Z]*\b
+\bEOAC[_A-Z]*\b
+\b(?:RPC_C_AUTHN_)?WINNT\b
+\bUPDATEREGISTRY\b
+\b(?:CDS_)?UPDATEREGISTRY\b
+
+# Display interface terms (HDMI, DVI, DisplayPort)
+\b(?:HDMI|DVI|DisplayPort)(?:-\d+)?\b
+
+# 2D Region struct names
+\bDisplayConfig2?D?Region\b
+
 # Microsoft Store URLs and product IDs
 ms-windows-store://\S+

.github/instructions/common-libraries.instructions.md

@@ -1,61 +0,0 @@
----
-description: 'Guidelines for shared libraries including logging, IPC, settings, DPI, telemetry, and utilities consumed by multiple modules'
-applyTo: 'src/common/**'
----
-
-# Common Libraries – Shared Code Guidance
-
-Guidelines for modifying shared code in `src/common/`. Changes here can have wide-reaching impact across the entire PowerToys codebase.
-
-## Scope
-
-- Logging infrastructure (`src/common/logger/`)
-- IPC primitives and named pipe utilities
-- Settings serialization and management
-- DPI awareness and scaling utilities
-- Telemetry helpers
-- General utilities (JSON parsing, string helpers, etc.)
-
-## Guidelines
-
-### API Stability
-
-- Avoid breaking public headers/APIs; if changed, search & update all callers
-- Coordinate ABI-impacting struct/class layout changes; keep binary compatibility
-- When modifying public interfaces, grep the entire codebase for usages
-
-### Performance
-
-- Watch perf in hot paths (hooks, timers, serialization)
-- Avoid avoidable allocations in frequently called code
-- Profile changes that touch performance-sensitive areas
-
-### Dependencies
-
-- Ask before adding third-party deps or changing serialization formats
-- New dependencies must be MIT-licensed or approved by PM team
-- Add any new external packages to `NOTICE.md`
-
-### Logging
-
-- C++ logging uses spdlog (`Logger::info`, `Logger::warn`, `Logger::error`, `Logger::debug`)
-- Initialize with `init_logger()` early in startup
-- Keep hot paths quiet – no logging in tight loops or hooks
-
-## Acceptance Criteria
-
-- No unintended ABI breaks
-- No noisy logs in hot paths
-- New non-obvious symbols briefly commented
-- All callers updated when interfaces change
-
-## Code Style
-
-- **C++**: Follow `.clang-format` in `src/`; use Modern C++ patterns per C++ Core Guidelines
-- **C#**: Follow `src/.editorconfig`; enforce StyleCop.Analyzers
-
-## Validation
-
-- Build: `tools\build\build.cmd` from `src/common/` folder
-- Verify no ABI breaks: grep for changed function/struct names across codebase
-- Check logs: ensure no new logging in performance-critical paths

.github/instructions/runner-settings-ui.instructions.md

@@ -1,68 +0,0 @@
----
-description: 'Guidelines for Runner and Settings UI components that communicate via named pipes and manage module lifecycle'
-applyTo: 'src/runner/**,src/settings-ui/**'
----
-
-# Runner & Settings UI – Core Components Guidance
-
-Guidelines for modifying the Runner (tray/module loader) and Settings UI (configuration app). These components communicate via Windows Named Pipes using JSON messages.
-
-## Runner (`src/runner/`)
-
-### Scope
-
-- Module bootstrap, hotkey management, settings bridge, update/elevation handling
-
-### Guidelines
-
-- If IPC/JSON contracts change, mirror updates in `src/settings-ui/**`
-- Keep module discovery in `src/runner/main.cpp` in sync when adding/removing modules
-- Keep startup lean: avoid blocking/network calls in early init path
-- Preserve GPO & elevation behaviors; confirm no regression in policy handling
-- Ask before modifying update workflow or elevation logic
-
-### Acceptance Criteria
-
-- Stable startup, consistent contracts, no unnecessary logging noise
-
-## Settings UI (`src/settings-ui/`)
-
-### Scope
-
-- WinUI/WPF UI, communicates with Runner over named pipes; manages persisted settings schema
-
-### Guidelines
-
-- Don't break settings schema silently; add migration when shape changes
-- If IPC/JSON contracts change, align with `src/runner/**` implementation
-- Keep UI responsive: marshal to UI thread for UI-bound operations
-- Reuse existing styles/resources; avoid duplicate theme keys
-- Add/adjust migration or serialization tests when changing persisted settings
-
-### Acceptance Criteria
-
-- Schema integrity preserved, responsive UI, consistent contracts, no style duplication
-
-## Shared Concerns
-
-### IPC Contract Changes
-
-When modifying the JSON message format between Runner and Settings UI:
-
-1. Update both `src/runner/` and `src/settings-ui/` in the same PR
-2. Preserve backward compatibility where possible
-3. Add migration logic for settings schema changes
-4. Test both directions of communication
-
-### Code Style
-
-- **C++ (Runner)**: Follow `.clang-format` in `src/`
-- **C# (Settings UI)**: Follow `src/.editorconfig`, use StyleCop.Analyzers
-- **XAML**: Use XamlStyler or run `.\.pipelines\applyXamlStyling.ps1 -Main`
-
-## Validation
-
-- Build Runner: `tools\build\build.cmd` from `src/runner/`
-- Build Settings UI: `tools\build\build.cmd` from `src/settings-ui/`
-- Test IPC: Launch both Runner and Settings UI, verify communication works
-- Schema changes: Run serialization tests if settings shape changed

.pipelines/ESRPSigning_core.json

@@ -210,6 +210,11 @@
             "PowerToys.PowerAccentModuleInterface.dll",
             "PowerToys.PowerAccentKeyboardService.dll",
 
+            "PowerToys.PowerDisplayModuleInterface.dll",
+            "WinUI3Apps\\PowerToys.PowerDisplay.dll",
+            "WinUI3Apps\\PowerToys.PowerDisplay.exe",
+            "PowerDisplay.Lib.dll",
+
             "WinUI3Apps\\PowerToys.PowerRenameExt.dll",
             "WinUI3Apps\\PowerToys.PowerRename.exe",
             "WinUI3Apps\\PowerToys.PowerRenameContextMenu.dll",
@@ -378,6 +383,8 @@
                 "UnitsNet.dll",
                 "UtfUnknown.dll",
                 "Wpf.Ui.dll",
+                "WmiLight.dll",
+                "WmiLight.Native.dll",
                 "Shmuelie.WinRTServer.dll",
                 "ToolGood.Words.Pinyin.dll"
             ],

Directory.Packages.props

@@ -63,7 +63,7 @@
     <PackageVersion Include="Microsoft.SemanticKernel.Connectors.MistralAI" Version="1.66.0-alpha" />
     <PackageVersion Include="Microsoft.SemanticKernel.Connectors.Ollama" Version="1.66.0-alpha" />
     <PackageVersion Include="Microsoft.Toolkit.Uwp.Notifications" Version="7.1.2" />
-    <PackageVersion Include="Microsoft.Web.WebView2" Version="1.0.3179.45" />
+    <PackageVersion Include="Microsoft.Web.WebView2" Version="1.0.3405.78" />
     <!-- Package Microsoft.Win32.SystemEvents added as a hack for being able to exclude the runtime assets so they don't conflict with 8.0.1. This is a dependency of System.Drawing.Common but the 8.0.1 version wasn't published to nuget. -->
     <PackageVersion Include="Microsoft.Win32.SystemEvents" Version="9.0.10" />
     <PackageVersion Include="Microsoft.WindowsPackageManager.ComInterop" Version="1.10.340" />
@@ -77,10 +77,8 @@
     <PackageVersion Include="Microsoft.Windows.CsWinRT" Version="2.2.0" />
     <PackageVersion Include="Microsoft.Windows.ImplementationLibrary" Version="1.0.231216.1"/>
     <PackageVersion Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.26100.6901" />
-    <PackageVersion Include="Microsoft.WindowsAppSDK" Version="1.8.251106002" />
-    <PackageVersion Include="Microsoft.WindowsAppSDK.Foundation" Version="1.8.251104000" />
-    <PackageVersion Include="Microsoft.WindowsAppSDK.AI" Version="1.8.39" />
-    <PackageVersion Include="Microsoft.WindowsAppSDK.Runtime" Version="1.8.251106002" />
+    <PackageVersion Include="Microsoft.WindowsAppSDK" Version="2.0.0-experimental4" />
+    <PackageVersion Include="Microsoft.WindowsAppSDK.AI" Version="2.0.130-experimental" />
     <PackageVersion Include="Microsoft.Xaml.Behaviors.WinUI.Managed" Version="2.0.9" />
     <PackageVersion Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.39" />
     <PackageVersion Include="ModernWpfUI" Version="0.9.4" />
@@ -93,6 +91,7 @@
     <PackageVersion Include="NLog.Extensions.Logging" Version="5.3.8" />
     <PackageVersion Include="NLog.Schema" Version="5.2.8" />
     <PackageVersion Include="OpenAI" Version="2.5.0" />
+    <PackageVersion Include="Polly.Core" Version="8.6.5" />
     <PackageVersion Include="ReverseMarkdown" Version="4.1.0" />
     <PackageVersion Include="RtfPipe" Version="2.0.7677.4303" />
     <PackageVersion Include="ScipBe.Common.Office.OneNote" Version="3.0.1" />
@@ -104,6 +103,7 @@
     <PackageVersion Include="StyleCop.Analyzers" Version="1.2.0-beta.556" />
     <!-- Package System.CodeDom added as a hack for being able to exclude the runtime assets so they don't conflict with 8.0.1. This is a dependency of System.Management but the 8.0.1 version wasn't published to nuget. -->
     <PackageVersion Include="System.CodeDom" Version="9.0.10" />
+    <PackageVersion Include="System.Collections.Immutable" Version="9.0.0" />
     <PackageVersion Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
     <PackageVersion Include="System.ComponentModel.Composition" Version="9.0.10" />
     <PackageVersion Include="System.Configuration.ConfigurationManager" Version="9.0.10" />
@@ -133,6 +133,7 @@
     <PackageVersion Include="UnitsNet" Version="5.56.0" />
     <PackageVersion Include="UTF.Unknown" Version="2.6.0" />
     <PackageVersion Include="WinUIEx" Version="2.8.0" />
+    <PackageVersion Include="WmiLight" Version="6.14.0" />
     <PackageVersion Include="WPF-UI" Version="3.0.5" />
     <PackageVersion Include="WyHash" Version="1.0.5" />
     <PackageVersion Include="WixToolset.Heat" Version="5.0.2" />

NOTICE.md

@@ -10,6 +10,7 @@ This software incorporates material from third parties.
 - Installer/Runner
 - Measure tool
 - Peek
+- PowerDisplay
 - Registry Preview
 
 ## Utility: Color Picker
@@ -1519,6 +1520,35 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 ```
 
+## Utility: PowerDisplay
+
+### Twinkle Tray
+
+PowerDisplay's DDC/CI implementation references techniques from Twinkle Tray.
+
+**Source**: https://github.com/xanderfrangos/twinkle-tray
+
+MIT License
+
+Copyright © 2020 Xander Frangos
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
 
 ## NuGet Packages used by PowerToys
 
@@ -1557,6 +1587,7 @@ SOFTWARE.
 - NLog.Extensions.Logging
 - NLog.Schema
 - OpenAI
+- Polly.Core
 - ReverseMarkdown
 - ScipBe.Common.Office.OneNote
 - SharpCompress
@@ -1569,5 +1600,6 @@ SOFTWARE.
 - UnitsNet
 - UTF.Unknown
 - WinUIEx
+- WmiLight
 - WPF-UI
 - WyHash

PowerToys.slnx

@@ -55,6 +55,7 @@
       <Platform Solution="*|x64" Project="x64" />
     </Project>
     <Project Path="src/common/UnitTests-CommonLib/UnitTests-CommonLib.vcxproj" Id="1a066c63-64b3-45f8-92fe-664e1cce8077" />
+    <Project Path="src/common/UnitTests-CommonUtils/UnitTests-CommonUtils.vcxproj" Id="8b5cfb38-ccba-40a8-ad7a-89c57b070884" />
     <Project Path="src/common/updating/updating.vcxproj" Id="17da04df-e393-4397-9cf0-84dabe11032e" />
     <Project Path="src/common/version/version.vcxproj" Id="cc6e41ac-8174-4e8a-8d22-85dd7f4851df" />
   </Folder>
@@ -684,6 +685,23 @@
       <Deploy />
     </Project>
   </Folder>
+  <Folder Name="/modules/PowerDisplay/">
+    <Project Path="src/modules/powerdisplay/PowerDisplay.Lib/PowerDisplay.Lib.csproj">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+    <Project Path="src/modules/powerdisplay/PowerDisplay/PowerDisplay.csproj">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+    <Project Path="src/modules/powerdisplay/PowerDisplayModuleInterface/PowerDisplayModuleInterface.vcxproj" Id="d1234567-8901-2345-6789-abcdef012345" />
+  </Folder>
+  <Folder Name="/modules/PowerDisplay/Tests/">
+    <Project Path="src/modules/powerdisplay/PowerDisplay.Lib.UnitTests/PowerDisplay.Lib.UnitTests.csproj">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+  </Folder>
   <Folder Name="/modules/MeasureTool/">
     <Project Path="src/modules/MeasureTool/MeasureToolCore/PowerToys.MeasureToolCore.vcxproj" Id="54a93af7-60c7-4f6c-99d2-fbb1f75f853a">
       <BuildDependency Project="src/common/Display/Display.vcxproj" />
@@ -1041,6 +1059,16 @@
       <Platform Solution="*|x64" Project="x64" />
     </Project>
   </Folder>
+  <Folder Name="/tools/SettingsSearchEvaluation/">
+    <Project Path="tools/SettingsSearchEvaluation/SettingsSearchEvaluation.csproj">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+    <Project Path="tools/SettingsSearchEvaluation.Tests/SettingsSearchEvaluation.Tests.csproj">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+  </Folder>
   <Folder Name="/Solution Items/">
     <File Path=".vsconfig" />
     <File Path="Cpp.Build.props" />

SEMANTIC_SEARCH_API_SUMMARY.md

@@ -0,0 +1,244 @@
+# Windows App SDK Semantic Search API 总结
+
+## 1. 环境与依赖
+
+| 项目 | 版本/值 |
+|------|---------|
+| **Windows App SDK** | `2.0.0-experimental3` |
+| **.NET** | `net9.0-windows10.0.26100.0` |
+| **AI Search NuGet** | `Microsoft.WindowsAppSDK.AI` (2.0.57-experimental) |
+| **命名空间** | `Microsoft.Windows.AI.Search.Experimental.AppContentIndex` |
+| **应用类型** | WinUI 3 MSIX 打包应用 |
+
+---
+
+## 2. 核心 API
+
+### 2.1 索引管理
+```csharp
+// 创建/打开索引
+var result = AppContentIndexer.GetOrCreateIndex("indexName");
+if (result.Succeeded) {
+    _indexer = result.Indexer;
+    // result.Status: CreatedNew | OpenedExisting
+}
+
+// 等待索引能力就绪
+await _indexer.WaitForIndexCapabilitiesAsync();
+
+// 等待索引空闲（建索引完成）
+await _indexer.WaitForIndexingIdleAsync(TimeSpan.FromSeconds(120));
+
+// 清理
+_indexer.RemoveAll();  // 删除所有索引
+_indexer.Remove(id);   // 删除单个
+_indexer.Dispose();
+```
+
+### 2.2 添加内容到索引
+```csharp
+// 索引文本 → 自动建立 TextLexical + TextSemantic 索引
+IndexableAppContent textContent = AppManagedIndexableAppContent.CreateFromString(id, text);
+_indexer.AddOrUpdate(textContent);
+
+// 索引图片 → 自动建立 ImageSemantic + ImageOcr 索引
+IndexableAppContent imageContent = AppManagedIndexableAppContent.CreateFromBitmap(id, softwareBitmap);
+_indexer.AddOrUpdate(imageContent);
+```
+
+### 2.3 查询
+```csharp
+// 文本查询
+TextQueryOptions options = new TextQueryOptions {
+    Language = "en-US",                          // 可选
+    MatchScope = QueryMatchScope.Unconstrained,  // 匹配范围
+    TextMatchType = TextLexicalMatchType.Fuzzy   // Fuzzy | Exact
+};
+AppIndexTextQuery query = _indexer.CreateTextQuery(searchText, options);
+IReadOnlyList<TextQueryMatch> matches = query.GetNextMatches(5);
+
+// 图片查询
+ImageQueryOptions imgOptions = new ImageQueryOptions {
+    MatchScope = QueryMatchScope.Unconstrained,
+    ImageOcrTextMatchType = TextLexicalMatchType.Fuzzy
+};
+AppIndexImageQuery imgQuery = _indexer.CreateImageQuery(searchText, imgOptions);
+IReadOnlyList<ImageQueryMatch> imgMatches = imgQuery.GetNextMatches(5);
+```
+
+### 2.4 能力检查（只读）
+```csharp
+IndexCapabilities capabilities = _indexer.GetIndexCapabilities();
+
+bool textLexicalOK = capabilities.GetCapabilityState(IndexCapability.TextLexical)
+    .InitializationStatus == IndexCapabilityInitializationStatus.Initialized;
+bool textSemanticOK = capabilities.GetCapabilityState(IndexCapability.TextSemantic)
+    .InitializationStatus == IndexCapabilityInitializationStatus.Initialized;
+bool imageSemanticOK = capabilities.GetCapabilityState(IndexCapability.ImageSemantic)
+    .InitializationStatus == IndexCapabilityInitializationStatus.Initialized;
+bool imageOcrOK = capabilities.GetCapabilityState(IndexCapability.ImageOcr)
+    .InitializationStatus == IndexCapabilityInitializationStatus.Initialized;
+```
+
+---
+
+## 3. 四种索引能力
+
+| 能力 | 说明 | 触发方式 |
+|------|------|----------|
+| `TextLexical` | 词法/关键词搜索 | CreateFromString() 自动 |
+| `TextSemantic` | AI 语义搜索 (Embedding) | CreateFromString() 自动 |
+| `ImageSemantic` | 图像语义搜索 | CreateFromBitmap() 自动 |
+| `ImageOcr` | 图片 OCR 文字搜索 | CreateFromBitmap() 自动 |
+
+---
+
+## 4. 可控选项（有限）
+
+### TextQueryOptions
+| 属性 | 类型 | 说明 |
+|------|------|------|
+| `Language` | string | 查询语言（可选，如 "en-US"）|
+| `MatchScope` | QueryMatchScope | Unconstrained / Region / ContentItem |
+| `TextMatchType` | TextLexicalMatchType | **Fuzzy** / Exact（仅影响 Lexical）|
+
+### ImageQueryOptions
+| 属性 | 类型 | 说明 |
+|------|------|------|
+| `MatchScope` | QueryMatchScope | Unconstrained / Region / ContentItem |
+| `ImageOcrTextMatchType` | TextLexicalMatchType | **Fuzzy** / Exact（仅影响 OCR）|
+
+### 枚举值说明
+
+**QueryMatchScope:**
+- `Unconstrained` - 无约束，同时使用 Lexical + Semantic
+- `Region` - 限制在特定区域
+- `ContentItem` - 限制在单个内容项
+
+**TextLexicalMatchType:**
+- `Fuzzy` - 模糊匹配，允许拼写错误、近似词
+- `Exact` - 精确匹配，必须完全一致
+
+---
+
+## 5. 关键限制 ⚠️
+
+| 限制 | 说明 |
+|------|------|
+| **不能单独指定 Semantic/Lexical** | 系统自动同时使用所有可用能力 |
+| **Fuzzy/Exact 只影响 Lexical** | 对 Semantic 搜索无效 |
+| **能力检查是只读的** | `GetIndexCapabilities()` 只能查看，不能控制 |
+| **无相似度阈值** | 不能设置 Semantic 匹配的阈值 |
+| **无结果排序控制** | 无法指定按相关度或其他方式排序 |
+| **语言需手动传** | 不会自动检测，需开发者指定 |
+| **无相关度分数** | 查询结果不返回匹配分数 |
+
+---
+
+## 6. 典型使用流程
+
+```
+┌─────────────────────────────────────────────────────────┐
+│                    App 启动时                           │
+├─────────────────────────────────────────────────────────┤
+│ 1. GetOrCreateIndex("name")     // 创建/打开索引        │
+│ 2. WaitForIndexCapabilitiesAsync()  // 等待能力就绪     │
+│ 3. GetIndexCapabilities()        // 检查可用能力        │
+│ 4. IndexAll()                    // 索引所有数据        │
+│    ├─ CreateFromString() × N                           │
+│    └─ CreateFromBitmap() × N                           │
+│ 5. WaitForIndexingIdleAsync()    // 等待索引完成        │
+└─────────────────────────────────────────────────────────┘
+                         ↓
+┌─────────────────────────────────────────────────────────┐
+│                    运行时查询                            │
+├─────────────────────────────────────────────────────────┤
+│ 1. CreateTextQuery(text, options)   // 创建查询         │
+│ 2. query.GetNextMatches(N)          // 获取结果         │
+│ 3. 处理 TextQueryMatch / ImageQueryMatch               │
+└─────────────────────────────────────────────────────────┘
+                         ↓
+┌─────────────────────────────────────────────────────────┐
+│                    App 退出时                           │
+├─────────────────────────────────────────────────────────┤
+│ 1. _indexer.RemoveAll()             // 清理索引         │
+│ 2. _indexer.Dispose()               // 释放资源         │
+└─────────────────────────────────────────────────────────┘
+```
+
+---
+
+## 7. 查询结果处理
+
+```csharp
+// 文本查询结果
+foreach (var match in textMatches)
+{
+    if (match.ContentKind == QueryMatchContentKind.AppManagedText)
+    {
+        AppManagedTextQueryMatch textResult = (AppManagedTextQueryMatch)match;
+        string contentId = match.ContentId;      // 内容 ID
+        int offset = textResult.TextOffset;      // 匹配文本偏移
+        int length = textResult.TextLength;      // 匹配文本长度
+    }
+}
+
+// 图片查询结果
+foreach (var match in imageMatches)
+{
+    if (match.ContentKind == QueryMatchContentKind.AppManagedImage)
+    {
+        AppManagedImageQueryMatch imageResult = (AppManagedImageQueryMatch)match;
+        string contentId = imageResult.ContentId;  // 图片 ID
+    }
+}
+```
+
+---
+
+## 8. 能力变化监听
+
+```csharp
+// 监听索引能力变化
+_indexer.Listener.IndexCapabilitiesChanged += (indexer, capabilities) =>
+{
+    // 重新检查能力状态，更新 UI
+    LoadAppIndexCapabilities();
+};
+```
+
+---
+
+## 9. 结论
+
+这是一个**高度封装的黑盒 API**：
+
+### 优点 ✅
+- 简单易用，几行代码即可实现搜索
+- 自动处理 Lexical + Semantic
+- 支持文本和图片多模态搜索
+- 系统级集成，无需额外部署模型
+
+### 缺点 ❌
+- 无法精细控制搜索类型
+- 不能只用 Semantic Search
+- 选项有限，缺乏高级配置
+- 实验性 API，可能变更
+
+### 替代方案
+**如果需要纯 Semantic Search（向量搜索）**，建议：
+- 直接使用 Embedding 模型生成向量
+- 配合向量数据库（Azure Cosmos DB、FAISS、Qdrant 等）
+
+---
+
+## 10. 相关 NuGet 包
+
+```xml
+<PackageReference Include="Microsoft.WindowsAppSDK" Version="2.0.0-experimental3" />
+<PackageReference Include="Microsoft.WindowsAppSDK.AI" Version="2.0.57-experimental" />
+```
+
+---
+
+*文档生成日期: 2026-01-21*

doc/devdocs/modules/powerdisplay/mccsParserDesign.md

@@ -0,0 +1,223 @@
+# MCCS Capabilities String Parser - Recursive Descent Design
+
+## Overview
+
+This document describes the recursive descent parser implementation for DDC/CI MCCS (Monitor Control Command Set) capabilities strings.
+
+### Attention!
+This document and the code implement are generated by Copilot.
+
+## Grammar Definition (BNF)
+
+```bnf
+capabilities      ::= ['('] segment* [')']
+segment           ::= identifier '(' segment_content ')'
+segment_content   ::= text | vcp_entries | hex_list
+vcp_entries       ::= vcp_entry*
+vcp_entry         ::= hex_byte [ '(' hex_list ')' ]
+hex_list          ::= hex_byte*
+hex_byte          ::= [0-9A-Fa-f]{2}
+identifier        ::= [a-z_A-Z]+
+text              ::= [^()]+
+```
+
+## Example Input
+
+```
+(prot(monitor)type(lcd)model(PD3220U)cmds(01 02 03 07)vcp(10 12 14(04 05 06) 16 60(11 12 0F) DC DF)mccs_ver(2.2)vcpname(F0(Custom Setting)))
+```
+
+## Parser Architecture
+
+### Component Hierarchy
+
+```
+MccsCapabilitiesParser (main parser)
+├── ParseCapabilities()      → MccsParseResult
+├── ParseSegment()           → ParsedSegment?
+├── ParseBalancedContent()   → string
+├── ParseIdentifier()        → ReadOnlySpan<char>
+├── ApplySegment()           → void
+│   ├── ParseHexList()       → List<byte>
+│   ├── ParseVcpEntries()    → Dictionary<byte, VcpCodeInfo>
+│   └── ParseVcpNames()      → void
+│
+├── VcpEntryParser (sub-parser for vcp() content)
+│   └── TryParseEntry()      → VcpEntry
+│
+├── VcpNameParser (sub-parser for vcpname() content)
+│   └── TryParseEntry()      → (byte code, string name)
+│
+└── WindowParser (sub-parser for windowN() content)
+    ├── Parse()              → WindowCapability
+    └── ParseSubSegment()    → (name, content)?
+```
+
+### Design Principles
+
+1. **ref struct for Zero Allocation**
+   - Main parser uses `ref struct` to avoid heap allocation
+   - Works with `ReadOnlySpan<char>` for efficient string slicing
+   - No intermediate string allocations during parsing
+
+2. **Recursive Descent Pattern**
+   - Each grammar rule has a corresponding parse method
+   - Methods call each other recursively for nested structures
+   - Single-character lookahead via `Peek()`
+
+3. **Error Recovery**
+   - Errors are accumulated, not thrown
+   - Parser attempts to continue after errors
+   - Returns partial results when possible
+
+4. **Sub-parsers for Specialized Content**
+   - `VcpEntryParser` for VCP code entries
+   - `VcpNameParser` for custom VCP names
+   - Each sub-parser handles its own grammar subset
+
+## Parse Methods Detail
+
+### ParseCapabilities()
+Entry point. Handles optional outer parentheses and iterates through segments.
+
+```csharp
+private MccsParseResult ParseCapabilities()
+{
+    // Handle optional outer parens
+    // while (!IsAtEnd()) { ParseSegment() }
+    // Return result with accumulated errors
+}
+```
+
+### ParseSegment()
+Parses a single `identifier(content)` segment.
+
+```csharp
+private ParsedSegment? ParseSegment()
+{
+    // 1. ParseIdentifier()
+    // 2. Expect '('
+    // 3. ParseBalancedContent()
+    // 4. Expect ')'
+}
+```
+
+### ParseBalancedContent()
+Extracts content between balanced parentheses, handling nested parens.
+
+```csharp
+private string ParseBalancedContent()
+{
+    int depth = 1;
+    while (depth > 0) {
+        if (char == '(') depth++;
+        if (char == ')') depth--;
+    }
+}
+```
+
+### ParseVcpEntries()
+Delegates to `VcpEntryParser` for the specialized VCP entry grammar.
+
+```csharp
+vcp_entry ::= hex_byte [ '(' hex_list ')' ]
+
+Examples:
+- "10"           → code=0x10, values=[]
+- "14(04 05 06)" → code=0x14, values=[4, 5, 6]
+- "60(11 12 0F)" → code=0x60, values=[0x11, 0x12, 0x0F]
+```
+
+## Comparison with Other Approaches
+
+| Approach | Pros | Cons |
+|----------|------|------|
+| **Recursive Descent** (this) | Clear structure, handles nesting, extensible | More code |
+| **Regex** (DDCSharp) | Concise | Hard to debug, limited nesting |
+| **Mixed** (original) | Pragmatic | Inconsistent, hard to maintain |
+
+## Performance Characteristics
+
+- **Time Complexity**: O(n) where n = input length
+- **Space Complexity**: O(1) for parsing + O(m) for output where m = number of VCP codes
+- **Allocations**: Minimal - only for output structures
+
+## Supported Segments
+
+| Segment | Description | Parser |
+|---------|-------------|--------|
+| `prot(...)` | Protocol type | Direct assignment |
+| `type(...)` | Display type (lcd/crt) | Direct assignment |
+| `model(...)` | Model name | Direct assignment |
+| `cmds(...)` | Supported commands | ParseHexList |
+| `vcp(...)` | VCP code entries | VcpEntryParser |
+| `mccs_ver(...)` | MCCS version | Direct assignment |
+| `vcpname(...)` | Custom VCP names | VcpNameParser |
+| `windowN(...)` | PIP/PBP window capabilities | WindowParser |
+
+### Window Segment Format
+
+The `windowN` segment (where N is 1, 2, 3, etc.) describes PIP/PBP window capabilities:
+
+```
+window1(type(PIP) area(25 25 1895 1175) max(640 480) min(10 10) window(10))
+```
+
+| Sub-field | Format | Description |
+|-----------|--------|-------------|
+| `type` | `type(PIP)` or `type(PBP)` | Window type (Picture-in-Picture or Picture-by-Picture) |
+| `area` | `area(x1 y1 x2 y2)` | Window area coordinates in pixels |
+| `max` | `max(width height)` | Maximum window dimensions |
+| `min` | `min(width height)` | Minimum window dimensions |
+| `window` | `window(id)` | Window identifier |
+
+All sub-fields are optional; missing fields default to zero values.
+
+## Error Handling
+
+```csharp
+public readonly struct ParseError
+{
+    public int Position { get; }    // Character position
+    public string Message { get; }  // Human-readable error
+}
+
+public sealed class MccsParseResult
+{
+    public VcpCapabilities Capabilities { get; }
+    public IReadOnlyList<ParseError> Errors { get; }
+    public bool HasErrors => Errors.Count > 0;
+    public bool IsValid => !HasErrors && Capabilities.SupportedVcpCodes.Count > 0;
+}
+```
+
+## Usage Example
+
+```csharp
+// Parse capabilities string
+var result = MccsCapabilitiesParser.Parse(capabilitiesString);
+
+if (result.IsValid)
+{
+    var caps = result.Capabilities;
+    Console.WriteLine($"Model: {caps.Model}");
+    Console.WriteLine($"MCCS Version: {caps.MccsVersion}");
+    Console.WriteLine($"VCP Codes: {caps.SupportedVcpCodes.Count}");
+}
+
+if (result.HasErrors)
+{
+    foreach (var error in result.Errors)
+    {
+        Console.WriteLine($"Parse error at {error.Position}: {error.Message}");
+    }
+}
+```
+
+## Edge Cases Handled
+
+1. **Missing outer parentheses** (Apple Cinema Display)
+2. **No spaces between hex bytes** (`010203` vs `01 02 03`)
+3. **Nested parentheses** in VCP values
+4. **Unknown segments** (logged but not fatal)
+5. **Malformed input** (partial results returned)

doc/devdocs/readme.md

@@ -68,6 +68,7 @@ Once you've discussed your proposed feature/fix/etc. with a team member, and an
 - Add the `In progress` label to the issue, if not already present. Also add a `Cost-Small/Medium/Large` estimate and make sure all appropriate labels are set.
 - If you are a community contributor, you will not be able to add labels to the issue; in that case just add a comment saying that you have started work on the issue and try to give an estimate for the delivery date.
 - If the work item has a medium/large cost, using the markdown task list, list each sub item and update the list with a check mark after completing each sub item.
+- **Before opening a PR, ensure your changes build successfully locally and functionality tests pass.** This is especially important for AI-assisted (vibe coding) contributions—always verify AI-generated code works as intended. Exploratory PRs or draft PRs for discussion are exceptions.
 - When opening a PR, follow the PR template.
 - When you'd like the team to take a look (even if the work is not yet fully complete) mark the PR as 'Ready For Review' so that the team can review your work and provide comments, suggestions, and request changes. It may take several cycles, but the end result will be solid, testable, conformant code that is safe for us to merge.
 - When the PR is approved, let the owner of the PR merge it. For community contributions, the reviewer who approved the PR can also merge it.

doc/devdocs/sparse-package-investigation.md

@@ -0,0 +1,325 @@
+# Sparse Package + WinUI 3 调查报告
+
+## 背景
+
+PowerToys 希望使用 Windows App SDK 的 Semantic Search API (`AppContentIndexer.GetOrCreateIndex`) 来实现语义搜索功能。该 API 要求应用具有 **Package Identity**。
+
+## 问题现象
+
+### 1. Semantic Search API 调用失败
+
+在 [SemanticSearchIndex.cs](../../src/common/Common.Search/SemanticSearch/SemanticSearchIndex.cs) 中调用 `AppContentIndexer.GetOrCreateIndex(_indexName)` 时，抛出 COM 异常：
+
+```
+System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.
+   at WinRT.ExceptionHelpers.<ThrowExceptionForHR>g__Throw|39_0(Int32 hr)
+   at Microsoft.Windows.AI.Search.AppContentIndexer.GetOrCreateIndex(String indexName)
+```
+
+### 2. API 要求
+
+根据 [Windows App SDK 文档](https://learn.microsoft.com/en-us/windows/ai/apis/content-search)，Semantic Search API 需要：
+- Windows 11 24H2 或更高版本
+- NPU 硬件支持
+- **Package Identity**（应用需要有 MSIX 包标识）
+
+## Sparse Package 方案
+
+### 什么是 Sparse Package
+
+Sparse Package（稀疏包）是一种为非打包（unpackaged）Win32 应用提供 Package Identity 的技术，无需完整的 MSIX 打包。
+
+参考：[Grant package identity by packaging with external location](https://learn.microsoft.com/en-us/windows/apps/desktop/modernize/grant-identity-to-nonpackaged-apps)
+
+### 实现架构
+
+```
+PowerToysSparse.msix (仅包含 manifest 和图标)
+    │
+    ├── AppxManifest.xml  (声明应用和依赖)
+    ├── Square44x44Logo.png
+    ├── Square150x150Logo.png
+    └── StoreLogo.png
+
+ExternalLocation (指向实际应用目录)
+    │
+    └── ARM64\Debug\
+        ├── PowerToys.Settings.exe
+        ├── PowerToys.Settings.pri
+        └── ... (其他应用文件)
+```
+
+### 关键组件
+
+| 文件 | 位置 | 作用 |
+|------|------|------|
+| AppxManifest.xml | src/PackageIdentity/ | 定义 sparse package 的应用、依赖和能力 |
+| app.manifest | src/settings-ui/Settings.UI/ | 嵌入 exe 中，声明与 sparse package 的关联 |
+| BuildSparsePackage.ps1 | src/PackageIdentity/ | 构建和签名脚本 |
+
+### Publisher 配置
+
+**重要**：app.manifest 和 AppxManifest.xml 中的 Publisher 必须匹配。
+
+| 环境 | Publisher |
+|------|-----------|
+| 开发环境 | `CN=PowerToys Dev, O=PowerToys, L=Redmond, S=Washington, C=US` |
+| 生产环境 | `CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US` |
+
+BuildSparsePackage.ps1 会在本地构建时**自动**将 AppxManifest.xml 的 Publisher 替换为开发环境值，无需手动修改源码。
+
+## 当前问题：WinUI 3 + Sparse Package 崩溃
+
+### 现象
+
+当 Settings.exe（WinUI 3 应用）通过 sparse package 启动时，立即崩溃：
+
+```
+Microsoft.UI.Xaml.Markup.XamlParseException (-2144665590):
+Cannot locate resource from 'ms-appx:///Microsoft.UI.Xaml/Themes/themeresources.xaml'. [Line: 11 Position: 40]
+```
+
+### 新观察（2026-01-25）
+
+对齐 WinAppSDK 版本并恢复 app-local 运行时后，仍可复现**更早期**的崩溃（未写入 Settings 日志）：
+
+- Application Error / WER（AUMID 启动）：
+  - Faulting module: `CoreMessagingXP.dll`
+  - Exception code: `0xc0000602`
+  - Faulting module path: `C:\PowerToys\ARM64\Debug\WinUI3Apps\CoreMessagingXP.dll`
+- 暂时移除 `CoreMessagingXP.dll` 后，出现 .NET Runtime 1026：
+  - `COMException (0x80040111): ClassFactory cannot supply requested class`
+  - 发生在 `Microsoft.UI.Xaml.Application.Start(...)`
+
+这说明 **“themeresources.xaml 无法解析”并不是唯一/必现的失败模式**，app-local 运行时在 sparse identity 下可能存在更底层的初始化问题。
+
+### 新观察（2026-01-25 晚间）
+
+framework-dependent + bootstrap 方向有实质进展：
+
+- 设置 `WindowsAppSDKSelfContained=false`（仅在 `UseSparseIdentity=true` 时生效）
+- 添加 `WindowsAppSDKBootstrapAutoInitializeOptions_OnPackageIdentity_NoOp=true`
+- **从 ExternalLocation 根目录与 `WinUI3Apps` 目录移除 app-local WinAppSDK 运行时文件**
+  - 尤其是 `CoreMessagingXP.dll`，否则会优先加载并导致 `0xc0000602`
+- **保留/放回 bootstrap DLL**
+  - 必需：`Microsoft.WindowsAppRuntime.Bootstrap.Net.dll`
+  - 建议同时保留：`Microsoft.WindowsAppRuntime.Bootstrap.dll`
+
+按以上处理后，Settings 通过 AUMID 启动不再崩溃，日志写入恢复。
+
+### 根本原因分析
+
+1. **ms-appx:/// URI 机制**
+   - WinUI 3 使用 `ms-appx:///` URI 加载 XAML 资源
+   - 这个 URI scheme 依赖于 MSIX 包的资源索引系统
+
+2. **框架资源位置**
+   - `themeresources.xaml` 等主题资源在 Windows App Runtime 框架包中
+   - 框架包位置：`C:\Program Files\WindowsApps\Microsoft.WindowsAppRuntime.2.0-experimental4_*\`（应与 WinAppSDK 版本匹配）
+   - 资源编译在框架包的 `resources.pri` 中
+
+3. **WinAppSDK 版本/依赖不一致（更可能的原因）**
+   - 仓库当前引用 `Microsoft.WindowsAppSDK` **2.0.0-experimental4**（见 `Directory.Packages.props`）
+   - Sparse manifest 仍依赖 **Microsoft.WindowsAppRuntime.2.0-experimental3**（`MinVersion=0.676.658.0`）
+   - 通过包标识启动时会走框架包资源图，如果依赖版本不匹配，WinUI 资源解析可能失败，从而触发上述 `XamlParseException`
+   - 需要先对齐依赖版本，再判断是否是 sparse 本身限制
+
+4. **app-local 运行时在 sparse identity 下崩溃（已观测）**
+   - 即使对齐 WinAppSDK 版本，也可能在 `CoreMessagingXP.dll` 处崩溃（`0xc0000602`）
+   - 此时 Settings 日志不一定写入，需查看 Application Event Log
+
+4. **Sparse Package 的限制（待验证）**
+   - 之前推断 `ms-appx:///` 在 sparse package 下无法解析框架依赖资源
+   - 但在修正依赖版本之前无法下结论
+
+### 对比：WPF 应用可以工作
+
+WPF 应用（如 ImageResizer）使用 sparse package 时**可以正常工作**，因为：
+- WPF 不依赖 `ms-appx:///` URI
+- WPF 资源加载使用不同的机制
+
+## 已尝试的解决方案
+
+| 方案 | 结果 | 原因 |
+|------|------|------|
+| 复制 PRI 文件到根目录 | ❌ 失败 | `ms-appx:///` 不查找本地 PRI |
+| 复制 themeresources 到本地 | ❌ 失败 | 资源在 PRI 中，不是独立文件 |
+| 修改 Settings OutputPath 到根目录 | ❌ 失败 | 问题不在于应用资源位置 |
+| 复制框架 resources.pri | ❌ 失败 | `ms-appx:///` 机制问题 |
+| 对齐 WindowsAppRuntime 依赖版本 | ⏳ 待验证 | 先排除依赖不一致导致的资源解析失败 |
+| app-local 运行时（self-contained）+ sparse identity | ❌ 失败 | Application Error: `CoreMessagingXP.dll` / `0xc0000602` |
+| 移除 `CoreMessagingXP.dll` | ❌ 失败 | .NET Runtime 1026: `ClassFactory cannot supply requested class` |
+| framework-dependent + bootstrap + 清理 ExternalLocation 中 app-local 运行时 | ✅ 成功 | 需保留 `Microsoft.WindowsAppRuntime.Bootstrap*.dll` |
+| 将 resources.pri 打进 sparse MSIX | ✅ 成功 | MRT 可从包内 resources.pri 正常解析字符串 |
+
+## 当前代码状态
+
+### 已修正（建议保留）
+
+1. **Settings.UI 输出路径**
+   - 文件：`src/settings-ui/Settings.UI/PowerToys.Settings.csproj`
+   - 修改：恢复为 `WinUI3Apps`（避免破坏 runner/installer/脚本路径假设）
+
+2. **AppxManifest.xml 的 Executable 路径**
+   - 文件：`src/PackageIdentity/AppxManifest.xml`
+   - 修改：恢复为 `WinUI3Apps\PowerToys.Settings.exe`
+
+3. **AppxManifest.xml 的 WindowsAppRuntime 依赖**
+   - 文件：`src/PackageIdentity/AppxManifest.xml`
+   - 修改：更新为 `Microsoft.WindowsAppRuntime.2.0-experimental4`，`MinVersion=0.738.2207.0`（与 `Microsoft.WindowsAppSDK.Runtime` 2.0.0-experimental4 对齐）
+
+### 未修改（源码中保持生产配置）
+
+- AppxManifest.xml 的 Publisher 保持 Microsoft Corporation（脚本会自动替换）
+
+### 验证步骤（建议）
+
+1. **确认 WindowsAppRuntime 版本已安装**
+   - `Get-AppxPackage -Name Microsoft.WindowsAppRuntime.2.0-experimental4`
+   - 如缺失，可从 NuGet 缓存安装：  
+     `Add-AppxPackage -Path "$env:USERPROFILE\.nuget\packages\microsoft.windowsappsdk.runtime\2.0.0-experimental4\tools\MSIX\win10-x64\Microsoft.WindowsAppRuntime.2.0-experimental4.msix"`
+
+2. **构建并注册 sparse package**
+   - `.\src\PackageIdentity\BuildSparsePackage.ps1 -Platform x64 -Configuration Debug`
+   - `Add-AppxPackage -Path ".\x64\Debug\PowerToysSparse.msix" -ExternalLocation ".\x64\Debug"`
+
+3. **用包标识启动 Settings**
+   - AUMID：`Microsoft.PowerToys.SparseApp!PowerToys.SettingsUI`
+   - 预期：不再触发 `themeresources.xaml` 解析错误
+
+## 可能的解决方向
+
+### 方向 1：等待 Windows App SDK 修复
+
+- 可能是 Windows App SDK 的已知限制或 bug
+- 需要在 GitHub issues 中搜索或提交新 issue
+
+### 方向 2：使用完整 MSIX 打包
+
+- 不使用 sparse package，而是完整打包
+- 影响：改变部署模型，增加复杂性
+
+### 方向 3：创建非 WinUI 3 的 Helper 进程
+
+- 创建一个 Console App 或 WPF App 作为 helper
+- 该 helper 具有 package identity，专门调用 Semantic Search API
+- Settings 通过 IPC 与 helper 通信
+- 优点：不影响现有 Settings 架构
+
+### 方向 4：进一步调查 ms-appx:/// 解析
+
+- 研究是否有配置选项让 sparse package 正确解析框架资源
+- 可能需要深入 Windows App SDK 源码或联系微软
+
+### 方向 5：切换为 framework-dependent + Bootstrap（待验证）
+
+- 设置 `WindowsAppSDKSelfContained=false` 并**重新构建** Settings
+- 确保外部目录不再携带 app-local WinAppSDK 运行时
+- 让 `Bootstrap.TryInitialize(...)` 生效，走框架包动态依赖
+
+## 可复现的工作流（已验证 2026-01-25）
+
+目标：Settings 使用 sparse identity 启动，WinUI 资源/字符串正常加载。
+
+### 1) 构建 Settings（framework-dependent + bootstrap no-op）
+
+在 `PowerToys.Settings.csproj` 中添加（仅在 `UseSparseIdentity=true` 时生效）：
+
+```
+<PropertyGroup Condition="'$(UseSparseIdentity)'=='true'">
+  <WindowsAppSDKSelfContained>false</WindowsAppSDKSelfContained>
+  <WindowsAppSDKBootstrapAutoInitializeOptions_OnPackageIdentity_NoOp>true</WindowsAppSDKBootstrapAutoInitializeOptions_OnPackageIdentity_NoOp>
+</PropertyGroup>
+```
+
+构建：
+
+```
+MSBuild.exe src\settings-ui\Settings.UI\PowerToys.Settings.csproj /p:Platform=ARM64 /p:Configuration=Debug /p:UseSparseIdentity=true /m:1 /p:CL_MPCount=1 /nodeReuse:false
+```
+
+### 2) 清理 ExternalLocation 的 app-local WinAppSDK 运行时
+
+**必须移除** app-local WinAppSDK 运行时文件，否则会优先加载并崩溃（`CoreMessagingXP.dll` / `0xc0000602`）。
+
+需清理的目录：
+- `ARM64\Debug`（ExternalLocation 根）
+- `ARM64\Debug\WinUI3Apps`
+
+建议只移除 app-local WinAppSDK 相关文件（保留业务 DLL）。
+
+**保留/放回 bootstrap DLL（必要）：**
+- `Microsoft.WindowsAppRuntime.Bootstrap.dll`
+- `Microsoft.WindowsAppRuntime.Bootstrap.Net.dll`
+
+### 3) 生成与包名一致的 resources.pri
+
+关键点：resources.pri 的 **ResourceMap name 必须与包名一致**。
+
+使用 `makepri.exe new` 生成，确保 `/mn` 指向 sparse 包的 `AppxManifest.xml`：
+
+```
+makepri.exe new ^
+  /pr C:\PowerToys\src\settings-ui\Settings.UI ^
+  /cf C:\PowerToys\src\settings-ui\Settings.UI\obj\ARM64\Debug\priconfig.xml ^
+  /mn C:\PowerToys\src\PackageIdentity\AppxManifest.xml ^
+  /of C:\PowerToys\ARM64\Debug\resources.pri ^
+  /o
+```
+
+### 4) 将 resources.pri 打进 sparse MSIX
+
+在 `BuildSparsePackage.ps1` 中把 `resources.pri` 放入 staging（脚本已更新）：
+- 优先取 `ARM64\Debug\resources.pri`
+- 如果不存在则回退 `ARM64\Debug\WinUI3Apps\PowerToys.Settings.pri`
+
+重新打包：
+
+```
+.\src\PackageIdentity\BuildSparsePackage.ps1 -Platform ARM64 -Configuration Debug
+```
+
+### 5) 重新注册 sparse 包（如需先卸载）
+
+如果因为内容变更被阻止，先卸载再安装：
+
+```
+Get-AppxPackage -Name Microsoft.PowerToys.SparseApp | Remove-AppxPackage
+Add-AppxPackage -Path .\ARM64\Debug\PowerToysSparse.msix -ExternalLocation .\ARM64\Debug -ForceApplicationShutdown
+```
+
+### 6) 启动 Settings（验证）
+
+```
+Start-Process "shell:AppsFolder\Microsoft.PowerToys.SparseApp_djwsxzxb4ksa8!PowerToys.SettingsUI"
+```
+
+验证要点：
+- Settings 正常启动，UI 文本显示
+- 日志正常写入：`%LOCALAPPDATA%\Microsoft\PowerToys\Settings\Logs\0.0.1.0\`
+
+### 备注（可选）
+
+如果出现 `ms-appx:///CommunityToolkit...` 资源缺失，可将对应的 `.pri`（从 NuGet 缓存）复制到 `ARM64\Debug\WinUI3Apps`，但在 **resources.pri 已正确打包** 后通常不再需要。
+
+## 待确认事项
+
+1. [ ] WinUI 3 + Sparse Package 的兼容性问题是否有官方文档说明？
+2. [ ] 是否有其他项目成功实现 WinUI 3 + Sparse Package？
+3. [ ] Windows App SDK GitHub 上是否有相关 issue？
+4. [ ] 修正依赖版本后，Settings 是否能在 sparse identity 下正常启动？
+5. [ ] framework-dependent（Bootstrap）方式是否能在 sparse identity 下启动？
+
+## 相关文件
+
+- [SemanticSearchIndex.cs](../../src/common/Common.Search/SemanticSearch/SemanticSearchIndex.cs) - Semantic Search 实现
+- [AppxManifest.xml](../../src/PackageIdentity/AppxManifest.xml) - Sparse package manifest
+- [BuildSparsePackage.ps1](../../src/PackageIdentity/BuildSparsePackage.ps1) - 构建脚本
+- [app.manifest](../../src/settings-ui/Settings.UI/app.manifest) - Settings 应用 manifest
+- [PowerToys.Settings.csproj](../../src/settings-ui/Settings.UI/PowerToys.Settings.csproj) - Settings 项目文件
+
+## 参考链接
+
+- [Grant package identity by packaging with external location](https://learn.microsoft.com/en-us/windows/apps/desktop/modernize/grant-identity-to-nonpackaged-apps)
+- [Windows App SDK - Content Search API](https://learn.microsoft.com/en-us/windows/ai/apis/content-search)
+- [Windows App SDK GitHub Issues](https://github.com/microsoft/WindowsAppSDK/issues)

doc/specs/common-search-library.md

@@ -0,0 +1,496 @@
+# Common.Search Library Specification
+
+## Overview
+
+本文档描述 `Common.Search` 库的重构设计，目标是提供一个通用的、可插拔的搜索框架，支持多种搜索引擎实现（Fuzzy Match、Semantic Search 等）。
+
+## Goals
+
+1. **解耦** - 搜索引擎与数据源完全解耦
+2. **可插拔** - 支持替换不同的搜索引擎实现
+3. **泛型** - 不绑定特定业务类型（如 SettingEntry）
+4. **可组合** - 支持多引擎组合（即时 Fuzzy + 延迟 Semantic）
+5. **可复用** - 可被 PowerToys 多个模块使用
+
+## Architecture
+
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                      Consumer (e.g., Settings.UI)               │
+├─────────────────────────────────────────────────────────────────┤
+│  SettingsDataProvider        ← 业务特定的数据加载               │
+│  SettingsSearchService       ← 业务特定的搜索服务               │
+│  SettingEntry : ISearchable  ← 业务实体实现搜索契约             │
+└─────────────────────────────────────────────────────────────────┘
+                              │ uses
+                              ▼
+┌─────────────────────────────────────────────────────────────────┐
+│                      Common.Search (Library)                    │
+├─────────────────────────────────────────────────────────────────┤
+│                                                                 │
+│  ┌─────────────────────────────────────────────────────────┐   │
+│  │                    Core Abstractions                     │   │
+│  ├─────────────────────────────────────────────────────────┤   │
+│  │  ISearchable              ← 可搜索内容契约               │   │
+│  │  ISearchEngine<T>         ← 搜索引擎接口                 │   │
+│  │  SearchResult<T>          ← 统一结果模型                 │   │
+│  │  SearchOptions            ← 搜索选项                     │   │
+│  └─────────────────────────────────────────────────────────┘   │
+│                                                                 │
+│  ┌─────────────────────────────────────────────────────────┐   │
+│  │                    Implementations                       │   │
+│  ├─────────────────────────────────────────────────────────┤   │
+│  │  FuzzSearch/                                             │   │
+│  │  ├── FuzzSearchEngine<T>  ← 内存 Fuzzy 搜索              │   │
+│  │  ├── StringMatcher        ← 现有的模糊匹配算法           │   │
+│  │  └── MatchResult          ← Fuzzy 匹配结果               │   │
+│  │                                                          │   │
+│  │  SemanticSearch/                                         │   │
+│  │  ├── SemanticSearchEngine ← Windows AI Search 封装       │   │
+│  │  └── SemanticSearchCapabilities                          │   │
+│  │                                                          │   │
+│  │  CompositeSearch/                                        │   │
+│  │  └── CompositeSearchEngine<T> ← 多引擎组合               │   │
+│  └─────────────────────────────────────────────────────────┘   │
+│                                                                 │
+└─────────────────────────────────────────────────────────────────┘
+```
+
+## Core Interfaces
+
+### ISearchable
+
+定义可搜索内容的最小契约。
+
+```csharp
+namespace Common.Search;
+
+/// <summary>
+/// Defines a searchable item that can be indexed and searched.
+/// </summary>
+public interface ISearchable
+{
+    /// <summary>
+    /// Gets the unique identifier for this item.
+    /// </summary>
+    string Id { get; }
+
+    /// <summary>
+    /// Gets the primary searchable text (e.g., title, header).
+    /// </summary>
+    string SearchableText { get; }
+
+    /// <summary>
+    /// Gets optional secondary searchable text (e.g., description).
+    /// Returns null if not available.
+    /// </summary>
+    string? SecondarySearchableText { get; }
+}
+```
+
+### ISearchEngine&lt;T&gt;
+
+搜索引擎核心接口。
+
+```csharp
+namespace Common.Search;
+
+/// <summary>
+/// Defines a pluggable search engine that can index and search items.
+/// </summary>
+/// <typeparam name="T">The type of items to search, must implement ISearchable.</typeparam>
+public interface ISearchEngine<T> : IDisposable
+    where T : ISearchable
+{
+    /// <summary>
+    /// Gets a value indicating whether the engine is ready to search.
+    /// </summary>
+    bool IsReady { get; }
+
+    /// <summary>
+    /// Gets the engine capabilities.
+    /// </summary>
+    SearchEngineCapabilities Capabilities { get; }
+
+    /// <summary>
+    /// Initializes the search engine.
+    /// </summary>
+    Task InitializeAsync(CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Indexes a single item.
+    /// </summary>
+    Task IndexAsync(T item, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Indexes multiple items in batch.
+    /// </summary>
+    Task IndexBatchAsync(IEnumerable<T> items, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Removes an item from the index by its ID.
+    /// </summary>
+    Task RemoveAsync(string id, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Clears all indexed items.
+    /// </summary>
+    Task ClearAsync(CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Searches for items matching the query.
+    /// </summary>
+    Task<IReadOnlyList<SearchResult<T>>> SearchAsync(
+        string query,
+        SearchOptions? options = null,
+        CancellationToken cancellationToken = default);
+}
+```
+
+### SearchResult&lt;T&gt;
+
+统一的搜索结果模型。
+
+```csharp
+namespace Common.Search;
+
+/// <summary>
+/// Represents a search result with the matched item and scoring information.
+/// </summary>
+public sealed class SearchResult<T>
+    where T : ISearchable
+{
+    /// <summary>
+    /// Gets the matched item.
+    /// </summary>
+    public required T Item { get; init; }
+
+    /// <summary>
+    /// Gets the relevance score (higher is more relevant).
+    /// </summary>
+    public required double Score { get; init; }
+
+    /// <summary>
+    /// Gets the type of match that produced this result.
+    /// </summary>
+    public required SearchMatchKind MatchKind { get; init; }
+
+    /// <summary>
+    /// Gets the match details for highlighting (optional).
+    /// </summary>
+    public IReadOnlyList<MatchSpan>? MatchSpans { get; init; }
+}
+
+/// <summary>
+/// Represents a span of matched text for highlighting.
+/// </summary>
+public readonly record struct MatchSpan(int Start, int Length);
+
+/// <summary>
+/// Specifies the kind of match that produced a search result.
+/// </summary>
+public enum SearchMatchKind
+{
+    /// <summary>Exact text match.</summary>
+    Exact,
+
+    /// <summary>Fuzzy/approximate text match.</summary>
+    Fuzzy,
+
+    /// <summary>Semantic/AI-based match.</summary>
+    Semantic,
+
+    /// <summary>Combined match from multiple engines.</summary>
+    Composite,
+}
+```
+
+### SearchOptions
+
+搜索配置选项。
+
+```csharp
+namespace Common.Search;
+
+/// <summary>
+/// Options for configuring search behavior.
+/// </summary>
+public sealed class SearchOptions
+{
+    /// <summary>
+    /// Gets or sets the maximum number of results to return.
+    /// Default is 20.
+    /// </summary>
+    public int MaxResults { get; set; } = 20;
+
+    /// <summary>
+    /// Gets or sets the minimum score threshold (0.0 to 1.0).
+    /// Results below this score are filtered out.
+    /// Default is 0.0 (no filtering).
+    /// </summary>
+    public double MinScore { get; set; } = 0.0;
+
+    /// <summary>
+    /// Gets or sets the language hint for the search (e.g., "en-US").
+    /// </summary>
+    public string? Language { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to include match spans for highlighting.
+    /// Default is false.
+    /// </summary>
+    public bool IncludeMatchSpans { get; set; } = false;
+}
+```
+
+### SearchEngineCapabilities
+
+引擎能力描述。
+
+```csharp
+namespace Common.Search;
+
+/// <summary>
+/// Describes the capabilities of a search engine.
+/// </summary>
+public sealed class SearchEngineCapabilities
+{
+    /// <summary>
+    /// Gets a value indicating whether the engine supports fuzzy matching.
+    /// </summary>
+    public bool SupportsFuzzyMatch { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine supports semantic search.
+    /// </summary>
+    public bool SupportsSemanticSearch { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine persists the index to disk.
+    /// </summary>
+    public bool PersistsIndex { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine supports incremental indexing.
+    /// </summary>
+    public bool SupportsIncrementalIndex { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine supports match span highlighting.
+    /// </summary>
+    public bool SupportsMatchSpans { get; init; }
+}
+```
+
+## Implementations
+
+### FuzzSearchEngine&lt;T&gt;
+
+基于现有 StringMatcher 的内存搜索引擎。
+
+**特点：**
+- 纯内存，无持久化
+- 即时响应（毫秒级）
+- 支持 match spans 高亮
+- 基于字符的模糊匹配
+
+**Capabilities：**
+```csharp
+new SearchEngineCapabilities
+{
+    SupportsFuzzyMatch = true,
+    SupportsSemanticSearch = false,
+    PersistsIndex = false,
+    SupportsIncrementalIndex = true,
+    SupportsMatchSpans = true,
+}
+```
+
+### SemanticSearchEngine
+
+基于 Windows App SDK AI Search API 的语义搜索引擎。
+
+**特点：**
+- 系统管理的持久化索引
+- AI 驱动的语义理解
+- 需要模型初始化（可能较慢）
+- 可能不可用（依赖系统支持）
+
+**Capabilities：**
+```csharp
+new SearchEngineCapabilities
+{
+    SupportsFuzzyMatch = true,  // API 同时提供 lexical + semantic
+    SupportsSemanticSearch = true,
+    PersistsIndex = true,
+    SupportsIncrementalIndex = true,
+    SupportsMatchSpans = false,  // API 不返回详细位置
+}
+```
+
+**注意：** SemanticSearchEngine 不是泛型的，因为它需要将内容转换为字符串存入系统索引。实现时通过 `ISearchable` 接口提取文本。
+
+### CompositeSearchEngine&lt;T&gt;
+
+组合多个搜索引擎，支持 fallback 和结果合并。
+
+```csharp
+namespace Common.Search;
+
+/// <summary>
+/// A search engine that combines results from multiple engines.
+/// </summary>
+public sealed class CompositeSearchEngine<T> : ISearchEngine<T>
+    where T : ISearchable
+{
+    /// <summary>
+    /// Strategy for combining results from multiple engines.
+    /// </summary>
+    public enum CombineStrategy
+    {
+        /// <summary>Use first ready engine only.</summary>
+        FirstReady,
+
+        /// <summary>Merge results from all ready engines.</summary>
+        MergeAll,
+
+        /// <summary>Use primary, fallback to secondary if primary not ready.</summary>
+        PrimaryWithFallback,
+    }
+}
+```
+
+**典型用法：** Fuzzy 作为即时响应，Semantic 准备好后增强结果。
+
+## Directory Structure
+
+```
+src/common/Common.Search/
+├── Common.Search.csproj
+├── GlobalSuppressions.cs
+├── ISearchable.cs
+├── ISearchEngine.cs
+├── SearchResult.cs
+├── SearchOptions.cs
+├── SearchEngineCapabilities.cs
+├── SearchMatchKind.cs
+├── MatchSpan.cs
+│
+├── FuzzSearch/
+│   ├── FuzzSearchEngine.cs
+│   ├── StringMatcher.cs         (existing)
+│   ├── MatchOption.cs           (existing)
+│   ├── MatchResult.cs           (existing)
+│   └── SearchPrecisionScore.cs  (existing)
+│
+├── SemanticSearch/
+│   ├── SemanticSearchEngine.cs
+│   ├── SemanticSearchCapabilities.cs
+│   └── SemanticSearchAdapter.cs  (adapts ISearchable to Windows API)
+│
+└── CompositeSearch/
+    └── CompositeSearchEngine.cs
+```
+
+## Consumer Usage (Settings.UI)
+
+### SettingEntry 实现 ISearchable
+
+```csharp
+// Settings.UI.Library/SettingEntry.cs
+public struct SettingEntry : ISearchable
+{
+    // Existing properties...
+
+    // ISearchable implementation
+    public string Id => ElementUid ?? $"{PageTypeName}|{ElementName}";
+    public string SearchableText => Header ?? string.Empty;
+    public string? SecondarySearchableText => Description;
+}
+```
+
+### SettingsSearchService
+
+```csharp
+// Settings.UI/Services/SettingsSearchService.cs
+public sealed class SettingsSearchService : IDisposable
+{
+    private readonly ISearchEngine<SettingEntry> _engine;
+
+    public SettingsSearchService(ISearchEngine<SettingEntry> engine)
+    {
+        _engine = engine;
+    }
+
+    public async Task InitializeAsync(IEnumerable<SettingEntry> entries)
+    {
+        await _engine.InitializeAsync();
+        await _engine.IndexBatchAsync(entries);
+    }
+
+    public async Task<List<SettingEntry>> SearchAsync(string query, CancellationToken ct = default)
+    {
+        var results = await _engine.SearchAsync(query, cancellationToken: ct);
+        return results.Select(r => r.Item).ToList();
+    }
+}
+```
+
+### Startup Configuration
+
+```csharp
+// Option 1: Fuzzy only (default, immediate)
+var engine = new FuzzSearchEngine<SettingEntry>();
+
+// Option 2: Semantic only (requires Windows AI)
+var engine = new SemanticSearchAdapter<SettingEntry>("PowerToysSettings");
+
+// Option 3: Composite (best of both worlds)
+var engine = new CompositeSearchEngine<SettingEntry>(
+    primary: new SemanticSearchAdapter<SettingEntry>("PowerToysSettings"),
+    fallback: new FuzzSearchEngine<SettingEntry>(),
+    strategy: CombineStrategy.PrimaryWithFallback
+);
+
+var searchService = new SettingsSearchService(engine);
+await searchService.InitializeAsync(settingEntries);
+```
+
+## Migration Plan
+
+### Phase 1: Core Abstractions
+1. 创建 `ISearchable`, `ISearchEngine<T>`, `SearchResult<T>` 等核心接口
+2. 保持现有 FuzzSearch 代码不变
+
+### Phase 2: FuzzSearchEngine&lt;T&gt;
+1. 创建泛型 `FuzzSearchEngine<T>` 实现
+2. 内部复用现有 `StringMatcher`
+
+### Phase 3: SemanticSearchEngine
+1. 完善现有 `SemanticSearchEngine` 实现
+2. 创建 `SemanticSearchAdapter<T>` 桥接泛型接口
+
+### Phase 4: Settings.UI Migration
+1. `SettingEntry` 实现 `ISearchable`
+2. 创建 `SettingsSearchService`
+3. 迁移 `SearchIndexService` 到新架构
+4. 保持 API 兼容，逐步废弃旧方法
+
+### Phase 5: CompositeSearchEngine (Optional)
+1. 实现组合引擎
+2. 支持 Fuzzy + Semantic 混合搜索
+
+## Open Questions
+
+1. **是否需要支持图片搜索？** 当前 SemanticSearchEngine 支持 `IndexImage`，但 `ISearchable` 只有文本。如果需要图片，可能需要 `IImageSearchable` 扩展。
+
+2. **结果去重策略？** CompositeEngine 合并结果时，同一个 Item 可能被多个引擎匹配，如何去重和合并分数？
+
+3. **异步 vs 同步？** FuzzSearch 完全可以同步执行，但接口统一用 `Task` 是否合适？考虑提供同步重载？
+
+4. **索引更新策略？** 当 Settings 内容变化时（例如用户切换语言），如何高效更新索引？
+
+---
+
+*Document Version: 1.0*
+*Last Updated: 2026-01-21*

installer/PowerToysSetupCustomActionsVNext/CustomAction.cpp

@@ -1549,7 +1549,7 @@ UINT __stdcall TerminateProcessesCA(MSIHANDLE hInstall)
     }
     processes.resize(bytes / sizeof(processes[0]));
 
-    std::array<std::wstring_view, 44> processesToTerminate = {
+    std::array<std::wstring_view, 45> processesToTerminate = {
         L"PowerToys.PowerLauncher.exe",
         L"PowerToys.Settings.exe",
         L"PowerToys.AdvancedPaste.exe",
@@ -1565,6 +1565,7 @@ UINT __stdcall TerminateProcessesCA(MSIHANDLE hInstall)
         L"PowerToys.PowerRename.exe",
         L"PowerToys.ImageResizer.exe",
         L"PowerToys.LightSwitchService.exe",
+        L"PowerToys.PowerDisplay.exe",
         L"PowerToys.GcodeThumbnailProvider.exe",
         L"PowerToys.BgcodeThumbnailProvider.exe",
         L"PowerToys.PdfThumbnailProvider.exe",

installer/PowerToysSetupVNext/PowerDisplay.wxs

@@ -0,0 +1,29 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs"
+     xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util" >
+
+  <?include $(sys.CURRENTDIR)\Common.wxi?>
+
+  <?define PowerDisplayAssetsFiles=?>
+  <?define PowerDisplayAssetsFilesPath=$(var.BinDir)WinUI3Apps\Assets\PowerDisplay?>
+
+  <Fragment>
+    <!-- Power Display -->
+    <DirectoryRef Id="WinUI3AppsAssetsFolder">
+      <Directory Id="PowerDisplayAssetsInstallFolder" Name="PowerDisplay" />
+    </DirectoryRef>
+    <DirectoryRef Id="PowerDisplayAssetsInstallFolder" FileSource="$(var.PowerDisplayAssetsFilesPath)">
+    <!-- Generated by generateFileComponents.ps1 -->
+    <!--PowerDisplayAssetsFiles_Component_Def-->
+    </DirectoryRef>
+
+    <ComponentGroup Id="PowerDisplayComponentGroup">
+      <Component Id="RemovePowerDisplayFolder" Guid="B8F2E3A5-72C1-4A2D-9B3F-8E5D7C6A4F9B" Directory="PowerDisplayAssetsInstallFolder" >
+        <RegistryKey Root="$(var.RegistryScope)" Key="Software\Classes\powertoys\components">
+          <RegistryValue Type="string" Name="RemovePowerDisplayFolder" Value="" KeyPath="yes"/>
+        </RegistryKey>
+        <RemoveFolder Id="RemoveFolderPowerDisplayAssetsFolder" Directory="PowerDisplayAssetsInstallFolder" On="uninstall"/>
+      </Component>
+    </ComponentGroup>
+
+  </Fragment>
+</Wix>

installer/PowerToysSetupVNext/PowerToysInstallerVNext.wixproj

@@ -47,6 +47,7 @@ call powershell.exe -NonInteractive -executionpolicy Unrestricted -File $(MSBuil
       call move /Y ..\..\..\NewPlus.wxs.bk ..\..\..\NewPlus.wxs
       call move /Y ..\..\..\Peek.wxs.bk ..\..\..\Peek.wxs
       call move /Y ..\..\..\PowerRename.wxs.bk ..\..\..\PowerRename.wxs
+      call move /Y ..\..\..\PowerDisplay.wxs.bk ..\..\..\PowerDisplay.wxs
       call move /Y ..\..\..\Product.wxs.bk ..\..\..\Product.wxs
       call move /Y ..\..\..\RegistryPreview.wxs.bk ..\..\..\RegistryPreview.wxs
       call move /Y ..\..\..\Resources.wxs.bk ..\..\..\Resources.wxs
@@ -123,6 +124,7 @@ call powershell.exe -NonInteractive -executionpolicy Unrestricted -File $(MSBuil
     <Compile Include="KeyboardManager.wxs" />
     <Compile Include="Peek.wxs" />
     <Compile Include="PowerRename.wxs" />
+    <Compile Include="PowerDisplay.wxs" />
     <Compile Include="DscResources.wxs" />
     <Compile Include="RegistryPreview.wxs" />
     <Compile Include="Run.wxs" />

installer/PowerToysSetupVNext/Product.wxs

@@ -53,6 +53,7 @@
       <ComponentGroupRef Id="LightSwitchComponentGroup" />
       <ComponentGroupRef Id="PeekComponentGroup" />
       <ComponentGroupRef Id="PowerRenameComponentGroup" />
+      <ComponentGroupRef Id="PowerDisplayComponentGroup" />
       <ComponentGroupRef Id="RegistryPreviewComponentGroup" />
       <ComponentGroupRef Id="RunComponentGroup" />
       <ComponentGroupRef Id="SettingsComponentGroup" />
@@ -146,7 +147,7 @@
       <Custom Action="UnRegisterCmdPalPackage" Before="RemoveFiles" Condition="Installed AND (NOT UPGRADINGPRODUCTCODE) AND (REMOVE=&quot;ALL&quot;)" />
       <Custom Action="UninstallCommandNotFound" Before="RemoveFiles" Condition="Installed AND (NOT UPGRADINGPRODUCTCODE) AND (REMOVE=&quot;ALL&quot;)" />
       <Custom Action="UpgradeCommandNotFound" After="InstallFiles" Condition="WIX_UPGRADE_DETECTED" />
-      <Custom Action="UninstallPackageIdentityMSIX" Before="RemoveFiles" Condition="Installed AND (NOT UPGRADINGPRODUCTCODE) AND (REMOVE=&quot;ALL&quot;)" />
+      <Custom Action="UninstallPackageIdentityMSIX" Before="RemoveFiles" Condition="Installed AND (REMOVE=&quot;ALL&quot;)" />
       <Custom Action="UninstallServicesTask" After="InstallFinalize" Condition="Installed AND (NOT UPGRADINGPRODUCTCODE) AND (REMOVE=&quot;ALL&quot;)" />
         <!-- TODO: Use to activate embedded MSIX -->
       <!--<Custom Action="UninstallEmbeddedMSIXTask" After="InstallFinalize">

installer/PowerToysSetupVNext/Resources.wxs

@@ -367,6 +367,12 @@
         </RegistryKey>
         <File Id="BgcodePreviewHandler_$(var.IdSafeLanguage)_File" Source="$(var.BinDir)\$(var.Language)\PowerToys.BgcodePreviewHandler.resources.dll" />
       </Component>
+      <Component Id="CmdPalExtPowerToys_$(var.IdSafeLanguage)_Component" Directory="Resource$(var.IdSafeLanguage)INSTALLFOLDER" Guid="$(var.CompGUIDPrefix)23">
+        <RegistryKey Root="$(var.RegistryScope)" Key="Software\Classes\powertoys\components">
+          <RegistryValue Type="string" Name="CmdPalExtPowerToys_$(var.IdSafeLanguage)_Component" Value="" KeyPath="yes" />
+        </RegistryKey>
+        <File Id="CmdPalExtPowerToys_$(var.IdSafeLanguage)_File" Source="$(var.BinDir)\$(var.Language)\Microsoft.CmdPal.Ext.PowerToys.resources.dll" />
+      </Component>
       <?undef IdSafeLanguage?>
       <?undef CompGUIDPrefix?>
       <?endforeach?>

installer/PowerToysSetupVNext/generateAllFileComponents.ps1

@@ -176,6 +176,10 @@ Generate-FileComponents -fileListName "ImageResizerAssetsFiles" -wxsFilePath $PS
 Generate-FileList -fileDepsJson "" -fileListName LightSwitchFiles -wxsFilePath $PSScriptRoot\LightSwitch.wxs -depsPath "$PSScriptRoot..\..\..\$platform\Release\LightSwitchService"
 Generate-FileComponents -fileListName "LightSwitchFiles" -wxsFilePath $PSScriptRoot\LightSwitch.wxs
 
+#PowerDisplay
+Generate-FileList -fileDepsJson "" -fileListName PowerDisplayAssetsFiles -wxsFilePath $PSScriptRoot\PowerDisplay.wxs -depsPath "$PSScriptRoot..\..\..\$platform\Release\WinUI3Apps\Assets\PowerDisplay"
+Generate-FileComponents -fileListName "PowerDisplayAssetsFiles" -wxsFilePath $PSScriptRoot\PowerDisplay.wxs
+
 #New+
 Generate-FileList -fileDepsJson "" -fileListName NewPlusAssetsFiles -wxsFilePath $PSScriptRoot\NewPlus.wxs -depsPath "$PSScriptRoot..\..\..\$platform\Release\WinUI3Apps\Assets\NewPlus"
 Generate-FileComponents -fileListName "NewPlusAssetsFiles" -wxsFilePath $PSScriptRoot\NewPlus.wxs

src/PackageIdentity/AppxManifest.xml

@@ -29,6 +29,7 @@
   </Resources>
   <Dependencies>
     <TargetDeviceFamily Name="Windows.Desktop" MinVersion="10.0.19000.0" MaxVersionTested="10.0.26226.0" />
+    <PackageDependency Name="Microsoft.WindowsAppRuntime.2.0-experimental4" MinVersion="0.738.2207.0" Publisher="CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US" />
   </Dependencies>
   <Capabilities>
     <Capability Name="internetClient" />
@@ -80,6 +81,7 @@
       <Extensions>
         <com:Extension Category="windows.comServer">
           <com:ComServer>
+
             <com:ExeServer Executable="Microsoft.CmdPal.Ext.PowerToys.exe" Arguments="-RegisterProcessAsComServer" DisplayName="PowerToys Command Palette Extension">
               <com:Class Id="7EC02C7D-8F98-4A2E-9F23-B58C2C2F2B17" DisplayName="PowerToys Command Palette Extension" />
             </com:ExeServer>

src/PackageIdentity/BuildSparsePackage.ps1

@@ -320,6 +320,19 @@ try {
             }
         }
     }
+
+    # Include resources.pri in the sparse MSIX if available to enable MRT in packaged mode.
+    # Prefer a prebuilt resources.pri in output root; fall back to Settings pri.
+    $resourcesPriSource = Join-Path $outDir "resources.pri"
+    if (-not (Test-Path $resourcesPriSource)) {
+        $resourcesPriSource = Join-Path $outDir "WinUI3Apps\\PowerToys.Settings.pri"
+    }
+    if (Test-Path $resourcesPriSource) {
+        Copy-Item -Path $resourcesPriSource -Destination (Join-Path $stagingDir "resources.pri") -Force -ErrorAction SilentlyContinue
+        Write-BuildLog "Including resources.pri from: $resourcesPriSource" -Level Info
+    } else {
+        Write-BuildLog "resources.pri not found; strings may be missing in sparse identity." -Level Warning
+    }
     
     # Ensure publisher matches the dev certificate for local builds
     $manifestStagingPath = Join-Path $stagingDir 'AppxManifest.xml'

src/common/Common.Search/Common.Search.csproj

@@ -4,5 +4,16 @@
 
   <PropertyGroup>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CS8305</WarningsNotAsErrors>
   </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.WindowsAppSDK" />
+    <PackageReference Include="Microsoft.WindowsAppSDK.AI" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ManagedCommon\ManagedCommon.csproj" />
+  </ItemGroup>
 </Project>

src/common/Common.Search/FuzzSearch/FuzzSearchEngine`1.cs

@@ -0,0 +1,306 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections.Concurrent;
+using System.Globalization;
+using System.Text;
+
+namespace Common.Search.FuzzSearch;
+
+/// <summary>
+/// A search engine that uses fuzzy string matching for search.
+/// </summary>
+/// <typeparam name="T">The type of items to search.</typeparam>
+public sealed class FuzzSearchEngine<T> : ISearchEngine<T>
+    where T : ISearchable
+{
+    private readonly object _lockObject = new();
+    private readonly Dictionary<string, T> _itemsById = new();
+    private readonly Dictionary<string, (string PrimaryNorm, string? SecondaryNorm)> _normalizedCache = new();
+    private bool _isReady;
+    private bool _disposed;
+
+    /// <inheritdoc/>
+    public bool IsReady
+    {
+        get
+        {
+            lock (_lockObject)
+            {
+                return _isReady;
+            }
+        }
+    }
+
+    /// <inheritdoc/>
+    public SearchEngineCapabilities Capabilities { get; } = new()
+    {
+        SupportsFuzzyMatch = true,
+        SupportsSemanticSearch = false,
+        PersistsIndex = false,
+        SupportsIncrementalIndex = true,
+        SupportsMatchSpans = true,
+    };
+
+    /// <inheritdoc/>
+    public Task InitializeAsync(CancellationToken cancellationToken = default)
+    {
+        lock (_lockObject)
+        {
+            _isReady = true;
+        }
+
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task IndexAsync(T item, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(item);
+        ThrowIfDisposed();
+
+        lock (_lockObject)
+        {
+            _itemsById[item.Id] = item;
+            _normalizedCache[item.Id] = (
+                NormalizeString(item.SearchableText),
+                item.SecondarySearchableText != null ? NormalizeString(item.SecondarySearchableText) : null
+            );
+        }
+
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task IndexBatchAsync(IEnumerable<T> items, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(items);
+        ThrowIfDisposed();
+
+        lock (_lockObject)
+        {
+            foreach (var item in items)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    break;
+                }
+
+                _itemsById[item.Id] = item;
+                _normalizedCache[item.Id] = (
+                    NormalizeString(item.SearchableText),
+                    item.SecondarySearchableText != null ? NormalizeString(item.SecondarySearchableText) : null
+                );
+            }
+        }
+
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task RemoveAsync(string id, CancellationToken cancellationToken = default)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(id);
+        ThrowIfDisposed();
+
+        lock (_lockObject)
+        {
+            _itemsById.Remove(id);
+            _normalizedCache.Remove(id);
+        }
+
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task ClearAsync(CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+
+        lock (_lockObject)
+        {
+            _itemsById.Clear();
+            _normalizedCache.Clear();
+        }
+
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task<IReadOnlyList<SearchResult<T>>> SearchAsync(
+        string query,
+        SearchOptions? options = null,
+        CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+
+        if (string.IsNullOrWhiteSpace(query))
+        {
+            return Task.FromResult<IReadOnlyList<SearchResult<T>>>(Array.Empty<SearchResult<T>>());
+        }
+
+        options ??= new SearchOptions();
+        var normalizedQuery = NormalizeString(query);
+
+        List<KeyValuePair<string, T>> snapshot;
+        lock (_lockObject)
+        {
+            if (_itemsById.Count == 0)
+            {
+                return Task.FromResult<IReadOnlyList<SearchResult<T>>>(Array.Empty<SearchResult<T>>());
+            }
+
+            snapshot = _itemsById.ToList();
+        }
+
+        var bag = new ConcurrentBag<SearchResult<T>>();
+        var po = new ParallelOptions
+        {
+            CancellationToken = cancellationToken,
+            MaxDegreeOfParallelism = Math.Max(1, Environment.ProcessorCount - 1),
+        };
+
+        try
+        {
+            Parallel.ForEach(snapshot, po, kvp =>
+            {
+                var (primaryNorm, secondaryNorm) = GetNormalizedTexts(kvp.Key);
+
+                var primaryResult = StringMatcher.FuzzyMatch(normalizedQuery, primaryNorm);
+                double score = primaryResult.Score;
+                List<int>? matchData = primaryResult.MatchData;
+
+                if (!string.IsNullOrEmpty(secondaryNorm))
+                {
+                    var secondaryResult = StringMatcher.FuzzyMatch(normalizedQuery, secondaryNorm);
+                    if (secondaryResult.Success && secondaryResult.Score * 0.8 > score)
+                    {
+                        score = secondaryResult.Score * 0.8;
+                        matchData = null; // Secondary matches don't have primary text spans
+                    }
+                }
+
+                if (score > options.MinScore)
+                {
+                    var result = new SearchResult<T>
+                    {
+                        Item = kvp.Value,
+                        Score = score,
+                        MatchKind = SearchMatchKind.Fuzzy,
+                        MatchSpans = options.IncludeMatchSpans && matchData != null
+                            ? ConvertToMatchSpans(matchData)
+                            : null,
+                    };
+
+                    bag.Add(result);
+                }
+            });
+        }
+        catch (OperationCanceledException)
+        {
+            return Task.FromResult<IReadOnlyList<SearchResult<T>>>(Array.Empty<SearchResult<T>>());
+        }
+
+        var results = bag
+            .OrderByDescending(r => r.Score)
+            .Take(options.MaxResults)
+            .ToList();
+
+        return Task.FromResult<IReadOnlyList<SearchResult<T>>>(results);
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        lock (_lockObject)
+        {
+            _itemsById.Clear();
+            _normalizedCache.Clear();
+            _isReady = false;
+        }
+
+        _disposed = true;
+    }
+
+    private (string PrimaryNorm, string? SecondaryNorm) GetNormalizedTexts(string id)
+    {
+        lock (_lockObject)
+        {
+            if (_normalizedCache.TryGetValue(id, out var cached))
+            {
+                return cached;
+            }
+        }
+
+        return (string.Empty, null);
+    }
+
+    private static IReadOnlyList<MatchSpan> ConvertToMatchSpans(List<int> matchData)
+    {
+        if (matchData == null || matchData.Count == 0)
+        {
+            return Array.Empty<MatchSpan>();
+        }
+
+        // Convert individual match indices to spans
+        var spans = new List<MatchSpan>();
+        var sortedIndices = matchData.OrderBy(i => i).ToList();
+
+        int start = sortedIndices[0];
+        int length = 1;
+
+        for (int i = 1; i < sortedIndices.Count; i++)
+        {
+            if (sortedIndices[i] == sortedIndices[i - 1] + 1)
+            {
+                // Consecutive index, extend the span
+                length++;
+            }
+            else
+            {
+                // Gap found, save current span and start new one
+                spans.Add(new MatchSpan(start, length));
+                start = sortedIndices[i];
+                length = 1;
+            }
+        }
+
+        // Add the last span
+        spans.Add(new MatchSpan(start, length));
+
+        return spans;
+    }
+
+    private static string NormalizeString(string? input)
+    {
+        if (string.IsNullOrEmpty(input))
+        {
+            return string.Empty;
+        }
+
+        var normalized = input.ToLowerInvariant().Normalize(NormalizationForm.FormKD);
+        var sb = new StringBuilder(normalized.Length);
+
+        foreach (var c in normalized)
+        {
+            var category = CharUnicodeInfo.GetUnicodeCategory(c);
+            if (category != UnicodeCategory.NonSpacingMark)
+            {
+                sb.Append(c);
+            }
+        }
+
+        return sb.ToString();
+    }
+
+    private void ThrowIfDisposed()
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+    }
+}

src/common/Common.Search/FuzzSearch/StringMatcher.cs

@@ -25,9 +25,9 @@ public class StringMatcher
     /// 6. Move onto the next substring's characters until all substrings are checked.
     /// 7. Consider success and move onto scoring if every char or substring without whitespaces matched
     /// </summary>
-    public static MatchResult FuzzyMatch(string query, string stringToCompare, MatchOption opt = null)
+    public static MatchResult FuzzyMatch(string query, string stringToCompare, MatchOption? opt = null)
     {
-        opt = opt ?? new MatchOption();
+        opt ??= new MatchOption();
 
         if (string.IsNullOrEmpty(stringToCompare))
         {

src/common/Common.Search/GlobalSuppressions.cs

@@ -11,6 +11,10 @@ using System.Diagnostics.CodeAnalysis;
 [assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.MatchResult._rawScore")]
 [assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.StringMatcher._defaultMatchOption")]
 [assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.StringMatcher._instance")]
+[assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.SemanticSearch.SemanticSearchIndex._indexName")]
+[assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.SemanticSearch.SemanticSearchIndex._indexer")]
+[assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.SemanticSearch.SemanticSearchIndex._disposed")]
+[assembly: SuppressMessage("StyleCop.CSharp.NamingRules", "SA1309:Field names should not begin with underscore", Justification = "coding style", Scope = "member", Target = "~F:Common.Search.SemanticSearch.SemanticSearchIndex._capabilities")]
 [assembly: SuppressMessage("StyleCop.CSharp.ReadabilityRules", "SA1101:Prefix local calls with this", Justification = "coding style", Scope = "member", Target = "~M:Common.Search.MatchResult.#ctor(System.Boolean,Common.Search.SearchPrecisionScore)")]
 [assembly: SuppressMessage("StyleCop.CSharp.ReadabilityRules", "SA1101:Prefix local calls with this", Justification = "coding style", Scope = "member", Target = "~M:Common.Search.MatchResult.#ctor(System.Boolean,Common.Search.SearchPrecisionScore,System.Collections.Generic.List{System.Int32},System.Int32)")]
 [assembly: SuppressMessage("Compiler", "CS8618:Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.", Justification = "Coding style", Scope = "member", Target = "~F:Common.Search.StringMatcher._instance")]

src/common/Common.Search/ISearchEngine`1.cs

@@ -0,0 +1,73 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Defines a pluggable search engine that can index and search items.
+/// </summary>
+/// <typeparam name="T">The type of items to search, must implement ISearchable.</typeparam>
+public interface ISearchEngine<T> : IDisposable
+    where T : ISearchable
+{
+    /// <summary>
+    /// Gets a value indicating whether the engine is ready to search.
+    /// </summary>
+    bool IsReady { get; }
+
+    /// <summary>
+    /// Gets the engine capabilities.
+    /// </summary>
+    SearchEngineCapabilities Capabilities { get; }
+
+    /// <summary>
+    /// Initializes the search engine.
+    /// </summary>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A task representing the async operation.</returns>
+    Task InitializeAsync(CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Indexes a single item.
+    /// </summary>
+    /// <param name="item">The item to index.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A task representing the async operation.</returns>
+    Task IndexAsync(T item, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Indexes multiple items in batch.
+    /// </summary>
+    /// <param name="items">The items to index.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A task representing the async operation.</returns>
+    Task IndexBatchAsync(IEnumerable<T> items, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Removes an item from the index by its ID.
+    /// </summary>
+    /// <param name="id">The ID of the item to remove.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A task representing the async operation.</returns>
+    Task RemoveAsync(string id, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Clears all indexed items.
+    /// </summary>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A task representing the async operation.</returns>
+    Task ClearAsync(CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Searches for items matching the query.
+    /// </summary>
+    /// <param name="query">The search query.</param>
+    /// <param name="options">Optional search options.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A list of search results ordered by relevance.</returns>
+    Task<IReadOnlyList<SearchResult<T>>> SearchAsync(
+        string query,
+        SearchOptions? options = null,
+        CancellationToken cancellationToken = default);
+}

src/common/Common.Search/ISearchable.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Defines a searchable item that can be indexed and searched.
+/// </summary>
+public interface ISearchable
+{
+    /// <summary>
+    /// Gets the unique identifier for this item.
+    /// </summary>
+    string Id { get; }
+
+    /// <summary>
+    /// Gets the primary searchable text (e.g., title, header).
+    /// </summary>
+    string SearchableText { get; }
+
+    /// <summary>
+    /// Gets optional secondary searchable text (e.g., description).
+    /// Returns null if not available.
+    /// </summary>
+    string? SecondarySearchableText { get; }
+}

src/common/Common.Search/MatchSpan.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Represents a span of matched text for highlighting.
+/// </summary>
+/// <param name="Start">The starting index of the match.</param>
+/// <param name="Length">The length of the match.</param>
+public readonly record struct MatchSpan(int Start, int Length);

src/common/Common.Search/SearchEngineCapabilities.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Describes the capabilities of a search engine.
+/// </summary>
+public sealed class SearchEngineCapabilities
+{
+    /// <summary>
+    /// Gets a value indicating whether the engine supports fuzzy matching.
+    /// </summary>
+    public bool SupportsFuzzyMatch { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine supports semantic search.
+    /// </summary>
+    public bool SupportsSemanticSearch { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine persists the index to disk.
+    /// </summary>
+    public bool PersistsIndex { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine supports incremental indexing.
+    /// </summary>
+    public bool SupportsIncrementalIndex { get; init; }
+
+    /// <summary>
+    /// Gets a value indicating whether the engine supports match span highlighting.
+    /// </summary>
+    public bool SupportsMatchSpans { get; init; }
+}

src/common/Common.Search/SearchError.cs

@@ -0,0 +1,134 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Represents an error that occurred during a search operation.
+/// </summary>
+public sealed class SearchError
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SearchError"/> class.
+    /// </summary>
+    /// <param name="code">The error code.</param>
+    /// <param name="message">The error message.</param>
+    /// <param name="details">Optional additional details.</param>
+    /// <param name="exception">Optional exception that caused the error.</param>
+    public SearchError(SearchErrorCode code, string message, string? details = null, Exception? exception = null)
+    {
+        Code = code;
+        Message = message;
+        Details = details;
+        Exception = exception;
+        Timestamp = DateTime.UtcNow;
+    }
+
+    /// <summary>
+    /// Gets the error code.
+    /// </summary>
+    public SearchErrorCode Code { get; }
+
+    /// <summary>
+    /// Gets the error message.
+    /// </summary>
+    public string Message { get; }
+
+    /// <summary>
+    /// Gets additional details about the error.
+    /// </summary>
+    public string? Details { get; }
+
+    /// <summary>
+    /// Gets the exception that caused the error, if any.
+    /// </summary>
+    public Exception? Exception { get; }
+
+    /// <summary>
+    /// Gets the timestamp when the error occurred.
+    /// </summary>
+    public DateTime Timestamp { get; }
+
+    /// <summary>
+    /// Creates an error for initialization failure.
+    /// </summary>
+    /// <param name="indexName">The name of the index.</param>
+    /// <param name="details">Optional details.</param>
+    /// <param name="exception">Optional exception.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError InitializationFailed(string indexName, string? details = null, Exception? exception = null)
+        => new(SearchErrorCode.InitializationFailed, $"Failed to initialize search index '{indexName}'.", details, exception);
+
+    /// <summary>
+    /// Creates an error for indexing failure.
+    /// </summary>
+    /// <param name="contentId">The ID of the content that failed to index.</param>
+    /// <param name="details">Optional details.</param>
+    /// <param name="exception">Optional exception.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError IndexingFailed(string contentId, string? details = null, Exception? exception = null)
+        => new(SearchErrorCode.IndexingFailed, $"Failed to index content '{contentId}'.", details, exception);
+
+    /// <summary>
+    /// Creates an error for search query failure.
+    /// </summary>
+    /// <param name="query">The search query that failed.</param>
+    /// <param name="details">Optional details.</param>
+    /// <param name="exception">Optional exception.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError SearchFailed(string query, string? details = null, Exception? exception = null)
+        => new(SearchErrorCode.SearchFailed, $"Search query '{query}' failed.", details, exception);
+
+    /// <summary>
+    /// Creates an error for engine not ready.
+    /// </summary>
+    /// <param name="operation">The operation that was attempted.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError EngineNotReady(string operation)
+        => new(SearchErrorCode.EngineNotReady, $"Search engine is not ready. Operation '{operation}' cannot be performed.");
+
+    /// <summary>
+    /// Creates an error for capability unavailable.
+    /// </summary>
+    /// <param name="capability">The capability that is unavailable.</param>
+    /// <param name="details">Optional details.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError CapabilityUnavailable(string capability, string? details = null)
+        => new(SearchErrorCode.CapabilityUnavailable, $"Search capability '{capability}' is not available.", details);
+
+    /// <summary>
+    /// Creates an error for timeout.
+    /// </summary>
+    /// <param name="operation">The operation that timed out.</param>
+    /// <param name="timeout">The timeout duration.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError Timeout(string operation, TimeSpan timeout)
+        => new(SearchErrorCode.Timeout, $"Operation '{operation}' timed out after {timeout.TotalSeconds:F1} seconds.");
+
+    /// <summary>
+    /// Creates an error for an unexpected error.
+    /// </summary>
+    /// <param name="operation">The operation that failed.</param>
+    /// <param name="exception">The exception that occurred.</param>
+    /// <returns>A new SearchError instance.</returns>
+    public static SearchError Unexpected(string operation, Exception exception)
+        => new(SearchErrorCode.Unexpected, $"Unexpected error during '{operation}'.", exception.Message, exception);
+
+    /// <inheritdoc/>
+    public override string ToString()
+    {
+        var result = $"[{Code}] {Message}";
+        if (!string.IsNullOrEmpty(Details))
+        {
+            result += $" Details: {Details}";
+        }
+
+        if (Exception != null)
+        {
+            result += $" Exception: {Exception.GetType().Name}: {Exception.Message}";
+        }
+
+        return result;
+    }
+}

src/common/Common.Search/SearchErrorCode.cs

@@ -0,0 +1,51 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Defines error codes for search operations.
+/// </summary>
+public enum SearchErrorCode
+{
+    /// <summary>
+    /// No error occurred.
+    /// </summary>
+    None = 0,
+
+    /// <summary>
+    /// The search engine failed to initialize.
+    /// </summary>
+    InitializationFailed = 1,
+
+    /// <summary>
+    /// Failed to index content.
+    /// </summary>
+    IndexingFailed = 2,
+
+    /// <summary>
+    /// The search query failed to execute.
+    /// </summary>
+    SearchFailed = 3,
+
+    /// <summary>
+    /// The search engine is not ready to perform the operation.
+    /// </summary>
+    EngineNotReady = 4,
+
+    /// <summary>
+    /// A required capability is not available.
+    /// </summary>
+    CapabilityUnavailable = 5,
+
+    /// <summary>
+    /// The operation timed out.
+    /// </summary>
+    Timeout = 6,
+
+    /// <summary>
+    /// An unexpected error occurred.
+    /// </summary>
+    Unexpected = 99,
+}

src/common/Common.Search/SearchMatchKind.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Specifies the kind of match that produced a search result.
+/// </summary>
+public enum SearchMatchKind
+{
+    /// <summary>
+    /// Exact text match.
+    /// </summary>
+    Exact,
+
+    /// <summary>
+    /// Fuzzy/approximate text match.
+    /// </summary>
+    Fuzzy,
+
+    /// <summary>
+    /// Semantic/AI-based match.
+    /// </summary>
+    Semantic,
+
+    /// <summary>
+    /// Combined match from multiple engines.
+    /// </summary>
+    Composite,
+}

src/common/Common.Search/SearchOperationResult.cs

@@ -0,0 +1,53 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Represents the result of a search operation that may have errors.
+/// </summary>
+public sealed class SearchOperationResult
+{
+    private SearchOperationResult(bool success, SearchError? error = null)
+    {
+        IsSuccess = success;
+        Error = error;
+    }
+
+    /// <summary>
+    /// Gets a value indicating whether the operation was successful.
+    /// </summary>
+    public bool IsSuccess { get; }
+
+    /// <summary>
+    /// Gets a value indicating whether the operation failed.
+    /// </summary>
+    public bool IsFailure => !IsSuccess;
+
+    /// <summary>
+    /// Gets the error if the operation failed, null otherwise.
+    /// </summary>
+    public SearchError? Error { get; }
+
+    /// <summary>
+    /// Creates a successful result.
+    /// </summary>
+    /// <returns>A successful SearchOperationResult.</returns>
+    public static SearchOperationResult Success() => new(true);
+
+    /// <summary>
+    /// Creates a failed result with the specified error.
+    /// </summary>
+    /// <param name="error">The error that caused the failure.</param>
+    /// <returns>A failed SearchOperationResult.</returns>
+    public static SearchOperationResult Failure(SearchError error)
+    {
+        ArgumentNullException.ThrowIfNull(error);
+        return new SearchOperationResult(false, error);
+    }
+
+    /// <inheritdoc/>
+    public override string ToString()
+        => IsSuccess ? "Success" : $"Failure: {Error}";
+}

src/common/Common.Search/SearchOperationResult1.cs

@@ -0,0 +1,87 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics.CodeAnalysis;
+
+#pragma warning disable SA1649 // File name should match first type name - Generic type file naming convention
+
+namespace Common.Search;
+
+/// <summary>
+/// Represents the result of a search operation that returns a value and may have errors.
+/// </summary>
+/// <typeparam name="T">The type of the result value.</typeparam>
+public sealed class SearchOperationResult<T>
+{
+    private SearchOperationResult(bool success, T? value, SearchError? error)
+    {
+        IsSuccess = success;
+        Value = value;
+        Error = error;
+    }
+
+    /// <summary>
+    /// Gets a value indicating whether the operation was successful.
+    /// </summary>
+    public bool IsSuccess { get; }
+
+    /// <summary>
+    /// Gets a value indicating whether the operation failed.
+    /// </summary>
+    public bool IsFailure => !IsSuccess;
+
+    /// <summary>
+    /// Gets the result value if the operation was successful.
+    /// </summary>
+    public T? Value { get; }
+
+    /// <summary>
+    /// Gets the error if the operation failed, null otherwise.
+    /// </summary>
+    public SearchError? Error { get; }
+
+    /// <summary>
+    /// Gets the value or a default if the operation failed.
+    /// </summary>
+    /// <param name="defaultValue">The default value to return if the operation failed.</param>
+    /// <returns>The value if successful, otherwise the default value.</returns>
+    public T GetValueOrDefault(T defaultValue) => IsSuccess && Value is not null ? Value : defaultValue;
+
+    /// <inheritdoc/>
+    public override string ToString()
+        => IsSuccess ? $"Success: {Value}" : $"Failure: {Error}";
+
+    /// <summary>
+    /// Creates a successful result with the specified value.
+    /// </summary>
+    /// <param name="value">The result value.</param>
+    /// <returns>A successful SearchOperationResult.</returns>
+    [SuppressMessage("Design", "CA1000:Do not declare static members on generic types", Justification = "Factory method pattern is the idiomatic way to create instances of generic result types")]
+    public static SearchOperationResult<T> Success(T value) => new(true, value, null);
+
+    /// <summary>
+    /// Creates a failed result with the specified error.
+    /// </summary>
+    /// <param name="error">The error that caused the failure.</param>
+    /// <returns>A failed SearchOperationResult.</returns>
+    [SuppressMessage("Design", "CA1000:Do not declare static members on generic types", Justification = "Factory method pattern is the idiomatic way to create instances of generic result types")]
+    public static SearchOperationResult<T> Failure(SearchError error)
+    {
+        ArgumentNullException.ThrowIfNull(error);
+        return new SearchOperationResult<T>(false, default, error);
+    }
+
+    /// <summary>
+    /// Creates a failed result with the specified error and a fallback value.
+    /// </summary>
+    /// <param name="error">The error that caused the failure.</param>
+    /// <param name="fallbackValue">A fallback value to use despite the failure.</param>
+    /// <returns>A failed SearchOperationResult with a fallback value.</returns>
+    [SuppressMessage("Design", "CA1000:Do not declare static members on generic types", Justification = "Factory method pattern is the idiomatic way to create instances of generic result types")]
+    public static SearchOperationResult<T> FailureWithFallback(SearchError error, T fallbackValue)
+    {
+        ArgumentNullException.ThrowIfNull(error);
+        return new SearchOperationResult<T>(false, fallbackValue, error);
+    }
+}

src/common/Common.Search/SearchOptions.cs

@@ -0,0 +1,35 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Options for configuring search behavior.
+/// </summary>
+public sealed class SearchOptions
+{
+    /// <summary>
+    /// Gets or sets the maximum number of results to return.
+    /// Default is 20.
+    /// </summary>
+    public int MaxResults { get; set; } = 20;
+
+    /// <summary>
+    /// Gets or sets the minimum score threshold.
+    /// Results below this score are filtered out.
+    /// Default is 0.0 (no filtering).
+    /// </summary>
+    public double MinScore { get; set; }
+
+    /// <summary>
+    /// Gets or sets the language hint for the search (e.g., "en-US").
+    /// </summary>
+    public string? Language { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to include match spans for highlighting.
+    /// Default is false.
+    /// </summary>
+    public bool IncludeMatchSpans { get; set; }
+}

src/common/Common.Search/SearchResult`1.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search;
+
+/// <summary>
+/// Represents a search result with the matched item and scoring information.
+/// </summary>
+/// <typeparam name="T">The type of the matched item.</typeparam>
+public sealed class SearchResult<T>
+    where T : ISearchable
+{
+    /// <summary>
+    /// Gets the matched item.
+    /// </summary>
+    public required T Item { get; init; }
+
+    /// <summary>
+    /// Gets the relevance score (higher is more relevant).
+    /// </summary>
+    public required double Score { get; init; }
+
+    /// <summary>
+    /// Gets the type of match that produced this result.
+    /// </summary>
+    public required SearchMatchKind MatchKind { get; init; }
+
+    /// <summary>
+    /// Gets the match details for highlighting (optional).
+    /// </summary>
+    public IReadOnlyList<MatchSpan>? MatchSpans { get; init; }
+}

src/common/Common.Search/SemanticSearch/SemanticSearchCapabilities.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// Represents the capabilities of the semantic search index.
+/// </summary>
+public class SemanticSearchCapabilities
+{
+    /// <summary>
+    /// Gets or sets a value indicating whether text lexical (keyword) search is available.
+    /// </summary>
+    public bool TextLexicalAvailable { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether text semantic (AI embedding) search is available.
+    /// </summary>
+    public bool TextSemanticAvailable { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether image semantic search is available.
+    /// </summary>
+    public bool ImageSemanticAvailable { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether image OCR search is available.
+    /// </summary>
+    public bool ImageOcrAvailable { get; set; }
+
+    /// <summary>
+    /// Gets a value indicating whether any search capability is available.
+    /// </summary>
+    public bool AnyAvailable => TextLexicalAvailable || TextSemanticAvailable || ImageSemanticAvailable || ImageOcrAvailable;
+
+    /// <summary>
+    /// Gets a value indicating whether text search (lexical or semantic) is available.
+    /// </summary>
+    public bool TextSearchAvailable => TextLexicalAvailable || TextSemanticAvailable;
+
+    /// <summary>
+    /// Gets a value indicating whether image search (semantic or OCR) is available.
+    /// </summary>
+    public bool ImageSearchAvailable => ImageSemanticAvailable || ImageOcrAvailable;
+}

src/common/Common.Search/SemanticSearch/SemanticSearchContentKind.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// Specifies the kind of content in a semantic search result.
+/// </summary>
+public enum SemanticSearchContentKind
+{
+    /// <summary>
+    /// Text content.
+    /// </summary>
+    Text,
+
+    /// <summary>
+    /// Image content.
+    /// </summary>
+    Image,
+}

src/common/Common.Search/SemanticSearch/SemanticSearchEngine`1.cs

@@ -0,0 +1,406 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using ManagedCommon;
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// A semantic search engine that implements the common search interface.
+/// </summary>
+/// <typeparam name="T">The type of items to search.</typeparam>
+public sealed class SemanticSearchEngine<T> : ISearchEngine<T>
+    where T : ISearchable
+{
+    private readonly SemanticSearchIndex _index;
+    private readonly Dictionary<string, T> _itemsById = new();
+    private readonly object _lockObject = new();
+    private bool _disposed;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SemanticSearchEngine{T}"/> class.
+    /// </summary>
+    /// <param name="indexName">The name of the search index.</param>
+    public SemanticSearchEngine(string indexName)
+    {
+        Logger.LogDebug($"[SemanticSearchEngine] Creating engine. IndexName={indexName}, ItemType={typeof(T).Name}");
+        _index = new SemanticSearchIndex(indexName);
+    }
+
+    /// <inheritdoc/>
+    public bool IsReady => _index.IsInitialized;
+
+    /// <inheritdoc/>
+    public SearchEngineCapabilities Capabilities { get; } = new()
+    {
+        SupportsFuzzyMatch = true,
+        SupportsSemanticSearch = true,
+        PersistsIndex = true,
+        SupportsIncrementalIndex = true,
+        SupportsMatchSpans = false,
+    };
+
+    /// <summary>
+    /// Gets the underlying semantic search capabilities.
+    /// </summary>
+    public SemanticSearchCapabilities? SemanticCapabilities => _index.Capabilities;
+
+    /// <summary>
+    /// Gets the last error that occurred during a search operation, or null if no error occurred.
+    /// </summary>
+    public SearchError? LastError => _index.LastError;
+
+    /// <summary>
+    /// Occurs when the semantic search capabilities change.
+    /// </summary>
+    public event EventHandler<SemanticSearchCapabilities>? CapabilitiesChanged
+    {
+        add => _index.CapabilitiesChanged += value;
+        remove => _index.CapabilitiesChanged -= value;
+    }
+
+    /// <inheritdoc/>
+    public async Task InitializeAsync(CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+        Logger.LogInfo($"[SemanticSearchEngine] InitializeAsync starting. ItemType={typeof(T).Name}");
+        var result = await _index.InitializeAsync().ConfigureAwait(false);
+
+        if (result.IsFailure)
+        {
+            Logger.LogWarning($"[SemanticSearchEngine] InitializeAsync failed. ItemType={typeof(T).Name}, Error={result.Error?.Message}");
+        }
+        else
+        {
+            Logger.LogInfo($"[SemanticSearchEngine] InitializeAsync completed. ItemType={typeof(T).Name}");
+        }
+
+        // Note: We don't throw here to maintain backward compatibility,
+        // but callers can check LastError for details if initialization failed.
+    }
+
+    /// <summary>
+    /// Initializes the search engine and returns the result with error details if any.
+    /// </summary>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public async Task<SearchOperationResult> InitializeWithResultAsync(CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+        return await _index.InitializeAsync().ConfigureAwait(false);
+    }
+
+    /// <inheritdoc/>
+    public Task IndexAsync(T item, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(item);
+        ThrowIfDisposed();
+
+        var text = BuildSearchableText(item);
+        if (string.IsNullOrWhiteSpace(text))
+        {
+            Logger.LogDebug($"[SemanticSearchEngine] IndexAsync skipped (empty text). Id={item.Id}");
+            return Task.CompletedTask;
+        }
+
+        lock (_lockObject)
+        {
+            _itemsById[item.Id] = item;
+        }
+
+        Logger.LogDebug($"[SemanticSearchEngine] IndexAsync. Id={item.Id}, TextLength={text.Length}");
+
+        // Note: Errors are captured in LastError for external logging
+        _ = _index.IndexText(item.Id, text);
+        return Task.CompletedTask;
+    }
+
+    /// <summary>
+    /// Indexes a single item and returns the result with error details if any.
+    /// </summary>
+    /// <param name="item">The item to index.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public Task<SearchOperationResult> IndexWithResultAsync(T item, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(item);
+        ThrowIfDisposed();
+
+        var text = BuildSearchableText(item);
+        if (string.IsNullOrWhiteSpace(text))
+        {
+            return Task.FromResult(SearchOperationResult.Success());
+        }
+
+        lock (_lockObject)
+        {
+            _itemsById[item.Id] = item;
+        }
+
+        return Task.FromResult(_index.IndexText(item.Id, text));
+    }
+
+    /// <inheritdoc/>
+    public Task IndexBatchAsync(IEnumerable<T> items, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(items);
+        ThrowIfDisposed();
+
+        var batch = new List<(string Id, string Text)>();
+
+        lock (_lockObject)
+        {
+            foreach (var item in items)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    Logger.LogDebug($"[SemanticSearchEngine] IndexBatchAsync cancelled. ItemsProcessed={batch.Count}");
+                    break;
+                }
+
+                var text = BuildSearchableText(item);
+                if (!string.IsNullOrWhiteSpace(text))
+                {
+                    _itemsById[item.Id] = item;
+                    batch.Add((item.Id, text));
+                }
+            }
+        }
+
+        Logger.LogInfo($"[SemanticSearchEngine] IndexBatchAsync. BatchSize={batch.Count}");
+
+        // Note: Errors are captured in LastError for external logging
+        _ = _index.IndexTextBatch(batch);
+        return Task.CompletedTask;
+    }
+
+    /// <summary>
+    /// Indexes multiple items in batch and returns the result with error details if any.
+    /// </summary>
+    /// <param name="items">The items to index.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public Task<SearchOperationResult> IndexBatchWithResultAsync(IEnumerable<T> items, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(items);
+        ThrowIfDisposed();
+
+        var batch = new List<(string Id, string Text)>();
+
+        lock (_lockObject)
+        {
+            foreach (var item in items)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    break;
+                }
+
+                var text = BuildSearchableText(item);
+                if (!string.IsNullOrWhiteSpace(text))
+                {
+                    _itemsById[item.Id] = item;
+                    batch.Add((item.Id, text));
+                }
+            }
+        }
+
+        return Task.FromResult(_index.IndexTextBatch(batch));
+    }
+
+    /// <inheritdoc/>
+    public Task RemoveAsync(string id, CancellationToken cancellationToken = default)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(id);
+        ThrowIfDisposed();
+
+        lock (_lockObject)
+        {
+            _itemsById.Remove(id);
+        }
+
+        Logger.LogDebug($"[SemanticSearchEngine] RemoveAsync. Id={id}");
+
+        // Note: Errors are captured in LastError for external logging
+        _ = _index.Remove(id);
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task ClearAsync(CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+
+        int count;
+        lock (_lockObject)
+        {
+            count = _itemsById.Count;
+            _itemsById.Clear();
+        }
+
+        Logger.LogInfo($"[SemanticSearchEngine] ClearAsync. ItemsCleared={count}");
+
+        // Note: Errors are captured in LastError for external logging
+        _ = _index.RemoveAll();
+        return Task.CompletedTask;
+    }
+
+    /// <inheritdoc/>
+    public Task<IReadOnlyList<SearchResult<T>>> SearchAsync(
+        string query,
+        SearchOptions? options = null,
+        CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+
+        if (string.IsNullOrWhiteSpace(query))
+        {
+            Logger.LogDebug($"[SemanticSearchEngine] SearchAsync skipped (empty query).");
+            return Task.FromResult<IReadOnlyList<SearchResult<T>>>(Array.Empty<SearchResult<T>>());
+        }
+
+        options ??= new SearchOptions();
+        Logger.LogDebug($"[SemanticSearchEngine] SearchAsync starting. Query={query}, MaxResults={options.MaxResults}");
+
+        var semanticOptions = new SemanticSearchOptions
+        {
+            MaxResults = options.MaxResults,
+            Language = options.Language,
+            MatchScope = SemanticSearchMatchScope.Unconstrained,
+            TextMatchType = SemanticSearchTextMatchType.Fuzzy,
+        };
+
+        var searchResult = _index.SearchText(query, semanticOptions);
+
+        // Note: Errors are captured in LastError for external logging
+        var matches = searchResult.Value ?? Array.Empty<SemanticSearchResult>();
+        var results = new List<SearchResult<T>>();
+
+        lock (_lockObject)
+        {
+            foreach (var match in matches)
+            {
+                if (_itemsById.TryGetValue(match.ContentId, out var item))
+                {
+                    results.Add(new SearchResult<T>
+                    {
+                        Item = item,
+                        Score = 100.0, // Semantic search doesn't return scores, use fixed value
+                        MatchKind = SearchMatchKind.Semantic,
+                        MatchSpans = null,
+                    });
+                }
+            }
+        }
+
+        Logger.LogDebug($"[SemanticSearchEngine] SearchAsync completed. Query={query}, Matches={matches.Count}, Results={results.Count}");
+        return Task.FromResult<IReadOnlyList<SearchResult<T>>>(results);
+    }
+
+    /// <summary>
+    /// Searches for items matching the query and returns the result with error details if any.
+    /// </summary>
+    /// <param name="query">The search query.</param>
+    /// <param name="options">Optional search options.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>A result containing search results or error details.</returns>
+    public Task<SearchOperationResult<IReadOnlyList<SearchResult<T>>>> SearchWithResultAsync(
+        string query,
+        SearchOptions? options = null,
+        CancellationToken cancellationToken = default)
+    {
+        ThrowIfDisposed();
+
+        if (string.IsNullOrWhiteSpace(query))
+        {
+            return Task.FromResult(SearchOperationResult<IReadOnlyList<SearchResult<T>>>.Success(Array.Empty<SearchResult<T>>()));
+        }
+
+        options ??= new SearchOptions();
+
+        var semanticOptions = new SemanticSearchOptions
+        {
+            MaxResults = options.MaxResults,
+            Language = options.Language,
+            MatchScope = SemanticSearchMatchScope.Unconstrained,
+            TextMatchType = SemanticSearchTextMatchType.Fuzzy,
+        };
+
+        var searchResult = _index.SearchText(query, semanticOptions);
+        var matches = searchResult.Value ?? Array.Empty<SemanticSearchResult>();
+        var results = new List<SearchResult<T>>();
+
+        lock (_lockObject)
+        {
+            foreach (var match in matches)
+            {
+                if (_itemsById.TryGetValue(match.ContentId, out var item))
+                {
+                    results.Add(new SearchResult<T>
+                    {
+                        Item = item,
+                        Score = 100.0,
+                        MatchKind = SearchMatchKind.Semantic,
+                        MatchSpans = null,
+                    });
+                }
+            }
+        }
+
+        if (searchResult.IsFailure)
+        {
+            return Task.FromResult(SearchOperationResult<IReadOnlyList<SearchResult<T>>>.FailureWithFallback(searchResult.Error!, results));
+        }
+
+        return Task.FromResult(SearchOperationResult<IReadOnlyList<SearchResult<T>>>.Success(results));
+    }
+
+    /// <summary>
+    /// Waits for the indexing process to complete.
+    /// </summary>
+    /// <param name="timeout">The maximum time to wait.</param>
+    /// <returns>A task representing the async operation.</returns>
+    public async Task WaitForIndexingCompleteAsync(TimeSpan timeout)
+    {
+        ThrowIfDisposed();
+        await _index.WaitForIndexingCompleteAsync(timeout).ConfigureAwait(false);
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        Logger.LogDebug($"[SemanticSearchEngine] Disposing. ItemType={typeof(T).Name}");
+        _index.Dispose();
+
+        lock (_lockObject)
+        {
+            _itemsById.Clear();
+        }
+
+        _disposed = true;
+    }
+
+    private static string BuildSearchableText(T item)
+    {
+        var primary = item.SearchableText ?? string.Empty;
+        var secondary = item.SecondarySearchableText;
+
+        if (string.IsNullOrWhiteSpace(secondary))
+        {
+            return primary;
+        }
+
+        return $"{primary} {secondary}";
+    }
+
+    private void ThrowIfDisposed()
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+    }
+}

src/common/Common.Search/SemanticSearch/SemanticSearchIndex.cs

@@ -0,0 +1,455 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using ManagedCommon;
+using Microsoft.Windows.Search.AppContentIndex;
+using Windows.Graphics.Imaging;
+using SearchOperationResult = Common.Search.SearchOperationResult;
+using SearchOperationResultT = Common.Search.SearchOperationResult<System.Collections.Generic.IReadOnlyList<Common.Search.SemanticSearch.SemanticSearchResult>>;
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// A semantic search engine powered by Windows App SDK AI Search APIs.
+/// Provides text and image indexing with lexical and semantic search capabilities.
+/// </summary>
+public sealed class SemanticSearchIndex : IDisposable
+{
+    private readonly string _indexName;
+    private AppContentIndexer? _indexer;
+    private bool _disposed;
+    private SemanticSearchCapabilities? _capabilities;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SemanticSearchIndex"/> class.
+    /// </summary>
+    /// <param name="indexName">The name of the search index.</param>
+    public SemanticSearchIndex(string indexName)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(indexName);
+        _indexName = indexName;
+    }
+
+    /// <summary>
+    /// Gets the last error that occurred during an operation, or null if no error occurred.
+    /// </summary>
+    public SearchError? LastError { get; private set; }
+
+    /// <summary>
+    /// Occurs when the index capabilities change.
+    /// </summary>
+    public event EventHandler<SemanticSearchCapabilities>? CapabilitiesChanged;
+
+    /// <summary>
+    /// Gets a value indicating whether the search engine is initialized.
+    /// </summary>
+    public bool IsInitialized => _indexer != null;
+
+    /// <summary>
+    /// Gets the current index capabilities, or null if not initialized.
+    /// </summary>
+    public SemanticSearchCapabilities? Capabilities => _capabilities;
+
+    /// <summary>
+    /// Initializes the search engine and creates or opens the index.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. Returns a result indicating success or failure with error details.</returns>
+    public async Task<SearchOperationResult> InitializeAsync()
+    {
+        ThrowIfDisposed();
+        LastError = null;
+
+        if (_indexer != null)
+        {
+            Logger.LogDebug($"[SemanticSearchIndex] Already initialized. IndexName={_indexName}");
+            return SearchOperationResult.Success();
+        }
+
+        Logger.LogInfo($"[SemanticSearchIndex] Initializing. IndexName={_indexName}");
+
+        try
+        {
+            var result = AppContentIndexer.GetOrCreateIndex(_indexName);
+            if (!result.Succeeded)
+            {
+                var errorDetails = $"Succeeded={result.Succeeded}, ExtendedError={result.ExtendedError}";
+                Logger.LogError($"[SemanticSearchIndex] GetOrCreateIndex failed. IndexName={_indexName}, {errorDetails}");
+                LastError = SearchError.InitializationFailed(_indexName, errorDetails);
+                return SearchOperationResult.Failure(LastError);
+            }
+
+            _indexer = result.Indexer;
+
+            // Wait for index capabilities to be ready
+            Logger.LogDebug($"[SemanticSearchIndex] Waiting for index capabilities. IndexName={_indexName}");
+            await _indexer.WaitForIndexCapabilitiesAsync();
+
+            // Load capabilities
+            _capabilities = LoadCapabilities();
+            Logger.LogInfo($"[SemanticSearchIndex] Initialized successfully. IndexName={_indexName}, TextLexical={_capabilities.TextLexicalAvailable}, TextSemantic={_capabilities.TextSemanticAvailable}, ImageSemantic={_capabilities.ImageSemanticAvailable}, ImageOcr={_capabilities.ImageOcrAvailable}");
+
+            // Subscribe to capability changes
+            _indexer.Listener.IndexCapabilitiesChanged += OnIndexCapabilitiesChanged;
+
+            return SearchOperationResult.Success();
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] Initialization failed with exception. IndexName={_indexName}", ex);
+            LastError = SearchError.InitializationFailed(_indexName, ex.Message, ex);
+            return SearchOperationResult.Failure(LastError);
+        }
+    }
+
+    /// <summary>
+    /// Waits for the indexing process to complete.
+    /// </summary>
+    /// <param name="timeout">The maximum time to wait for indexing to complete.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    public async Task WaitForIndexingCompleteAsync(TimeSpan timeout)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+
+        await _indexer!.WaitForIndexingIdleAsync(timeout);
+    }
+
+    /// <summary>
+    /// Gets the current index capabilities.
+    /// </summary>
+    /// <returns>The current capabilities of the search index.</returns>
+    public SemanticSearchCapabilities GetCapabilities()
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+
+        return _capabilities ?? LoadCapabilities();
+    }
+
+    /// <summary>
+    /// Adds or updates text content in the index.
+    /// </summary>
+    /// <param name="id">The unique identifier for the content.</param>
+    /// <param name="text">The text content to index.</param>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public SearchOperationResult IndexText(string id, string text)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+        ArgumentException.ThrowIfNullOrWhiteSpace(id);
+        ArgumentException.ThrowIfNullOrWhiteSpace(text);
+
+        try
+        {
+            var content = AppManagedIndexableAppContent.CreateFromString(id, text);
+            _indexer!.AddOrUpdate(content);
+            return SearchOperationResult.Success();
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] IndexText failed. Id={id}", ex);
+            LastError = SearchError.IndexingFailed(id, ex.Message, ex);
+            return SearchOperationResult.Failure(LastError);
+        }
+    }
+
+    /// <summary>
+    /// Adds or updates multiple text contents in the index.
+    /// </summary>
+    /// <param name="items">A collection of id-text pairs to index.</param>
+    /// <returns>A result indicating success or failure with error details. Contains the first error encountered if any.</returns>
+    public SearchOperationResult IndexTextBatch(IEnumerable<(string Id, string Text)> items)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+        ArgumentNullException.ThrowIfNull(items);
+
+        SearchError? firstError = null;
+
+        foreach (var (id, text) in items)
+        {
+            if (!string.IsNullOrWhiteSpace(id) && !string.IsNullOrWhiteSpace(text))
+            {
+                try
+                {
+                    var content = AppManagedIndexableAppContent.CreateFromString(id, text);
+                    _indexer!.AddOrUpdate(content);
+                }
+                catch (Exception ex)
+                {
+                    Logger.LogError($"[SemanticSearchIndex] IndexTextBatch item failed. Id={id}", ex);
+                    firstError ??= SearchError.IndexingFailed(id, ex.Message, ex);
+                }
+            }
+        }
+
+        if (firstError != null)
+        {
+            LastError = firstError;
+            return SearchOperationResult.Failure(firstError);
+        }
+
+        return SearchOperationResult.Success();
+    }
+
+    /// <summary>
+    /// Adds or updates image content in the index.
+    /// </summary>
+    /// <param name="id">The unique identifier for the image.</param>
+    /// <param name="bitmap">The image bitmap to index.</param>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public SearchOperationResult IndexImage(string id, SoftwareBitmap bitmap)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+        ArgumentException.ThrowIfNullOrWhiteSpace(id);
+        ArgumentNullException.ThrowIfNull(bitmap);
+
+        try
+        {
+            var content = AppManagedIndexableAppContent.CreateFromBitmap(id, bitmap);
+            _indexer!.AddOrUpdate(content);
+            return SearchOperationResult.Success();
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] IndexImage failed. Id={id}", ex);
+            LastError = SearchError.IndexingFailed(id, ex.Message, ex);
+            return SearchOperationResult.Failure(LastError);
+        }
+    }
+
+    /// <summary>
+    /// Removes content from the index by its identifier.
+    /// </summary>
+    /// <param name="id">The unique identifier of the content to remove.</param>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public SearchOperationResult Remove(string id)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+        ArgumentException.ThrowIfNullOrWhiteSpace(id);
+
+        try
+        {
+            _indexer!.Remove(id);
+            return SearchOperationResult.Success();
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] Remove failed. Id={id}", ex);
+            LastError = SearchError.Unexpected("Remove", ex);
+            return SearchOperationResult.Failure(LastError);
+        }
+    }
+
+    /// <summary>
+    /// Removes all content from the index.
+    /// </summary>
+    /// <returns>A result indicating success or failure with error details.</returns>
+    public SearchOperationResult RemoveAll()
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+
+        try
+        {
+            _indexer!.RemoveAll();
+            return SearchOperationResult.Success();
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] RemoveAll failed.", ex);
+            LastError = SearchError.Unexpected("RemoveAll", ex);
+            return SearchOperationResult.Failure(LastError);
+        }
+    }
+
+    /// <summary>
+    /// Searches for text content in the index.
+    /// </summary>
+    /// <param name="searchText">The text to search for.</param>
+    /// <param name="options">Optional search options.</param>
+    /// <returns>A result containing search results or error details.</returns>
+    public SearchOperationResultT SearchText(string searchText, SemanticSearchOptions? options = null)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+        ArgumentException.ThrowIfNullOrWhiteSpace(searchText);
+
+        options ??= new SemanticSearchOptions();
+
+        try
+        {
+            var queryOptions = new TextQueryOptions
+            {
+                MatchScope = ConvertMatchScope(options.MatchScope),
+                TextMatchType = ConvertTextMatchType(options.TextMatchType),
+            };
+
+            if (!string.IsNullOrEmpty(options.Language))
+            {
+                queryOptions.Language = options.Language;
+            }
+
+            var query = _indexer!.CreateTextQuery(searchText, queryOptions);
+            var matches = query.GetNextMatches(options.MaxResults);
+
+            return SearchOperationResultT.Success(ConvertTextMatches(matches));
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] SearchText failed. Query={searchText}", ex);
+            LastError = SearchError.SearchFailed(searchText, ex.Message, ex);
+            return SearchOperationResultT.FailureWithFallback(LastError, Array.Empty<SemanticSearchResult>());
+        }
+    }
+
+    /// <summary>
+    /// Searches for image content in the index using text.
+    /// </summary>
+    /// <param name="searchText">The text to search for in images.</param>
+    /// <param name="options">Optional search options.</param>
+    /// <returns>A result containing search results or error details.</returns>
+    public SearchOperationResultT SearchImages(string searchText, SemanticSearchOptions? options = null)
+    {
+        ThrowIfDisposed();
+        ThrowIfNotInitialized();
+        ArgumentException.ThrowIfNullOrWhiteSpace(searchText);
+
+        options ??= new SemanticSearchOptions();
+
+        try
+        {
+            var queryOptions = new ImageQueryOptions
+            {
+                MatchScope = ConvertMatchScope(options.MatchScope),
+                ImageOcrTextMatchType = ConvertTextMatchType(options.TextMatchType),
+            };
+
+            var query = _indexer!.CreateImageQuery(searchText, queryOptions);
+            var matches = query.GetNextMatches(options.MaxResults);
+
+            return SearchOperationResultT.Success(ConvertImageMatches(matches));
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"[SemanticSearchIndex] SearchImages failed. Query={searchText}", ex);
+            LastError = SearchError.SearchFailed(searchText, ex.Message, ex);
+            return SearchOperationResultT.FailureWithFallback(LastError, Array.Empty<SemanticSearchResult>());
+        }
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        if (_indexer != null)
+        {
+            _indexer.Listener.IndexCapabilitiesChanged -= OnIndexCapabilitiesChanged;
+            _indexer.Dispose();
+            _indexer = null;
+        }
+
+        _disposed = true;
+    }
+
+    private SemanticSearchCapabilities LoadCapabilities()
+    {
+        var capabilities = _indexer!.GetIndexCapabilities();
+
+        return new SemanticSearchCapabilities
+        {
+            TextLexicalAvailable = IsCapabilityInitialized(capabilities, IndexCapability.TextLexical),
+            TextSemanticAvailable = IsCapabilityInitialized(capabilities, IndexCapability.TextSemantic),
+            ImageSemanticAvailable = IsCapabilityInitialized(capabilities, IndexCapability.ImageSemantic),
+            ImageOcrAvailable = IsCapabilityInitialized(capabilities, IndexCapability.ImageOcr),
+        };
+    }
+
+    private static bool IsCapabilityInitialized(IndexCapabilities capabilities, IndexCapability capability)
+    {
+        var state = capabilities.GetCapabilityState(capability);
+        return state.InitializationStatus == IndexCapabilityInitializationStatus.Initialized;
+    }
+
+    private void OnIndexCapabilitiesChanged(AppContentIndexer indexer, IndexCapabilities capabilities)
+    {
+        _capabilities = LoadCapabilities();
+        Logger.LogInfo($"[SemanticSearchIndex] Capabilities changed. IndexName={_indexName}, TextLexical={_capabilities.TextLexicalAvailable}, TextSemantic={_capabilities.TextSemanticAvailable}, ImageSemantic={_capabilities.ImageSemanticAvailable}, ImageOcr={_capabilities.ImageOcrAvailable}");
+        CapabilitiesChanged?.Invoke(this, _capabilities);
+    }
+
+    private static QueryMatchScope ConvertMatchScope(SemanticSearchMatchScope scope)
+    {
+        return scope switch
+        {
+            SemanticSearchMatchScope.Unconstrained => QueryMatchScope.Unconstrained,
+            SemanticSearchMatchScope.Region => QueryMatchScope.Region,
+            SemanticSearchMatchScope.ContentItem => QueryMatchScope.ContentItem,
+            _ => QueryMatchScope.Unconstrained,
+        };
+    }
+
+    private static TextLexicalMatchType ConvertTextMatchType(SemanticSearchTextMatchType matchType)
+    {
+        return matchType switch
+        {
+            SemanticSearchTextMatchType.Fuzzy => TextLexicalMatchType.Fuzzy,
+            SemanticSearchTextMatchType.Exact => TextLexicalMatchType.Exact,
+            _ => TextLexicalMatchType.Fuzzy,
+        };
+    }
+
+    private static IReadOnlyList<SemanticSearchResult> ConvertTextMatches(IReadOnlyList<TextQueryMatch> matches)
+    {
+        var results = new List<SemanticSearchResult>();
+
+        foreach (var match in matches)
+        {
+            var result = new SemanticSearchResult(match.ContentId, SemanticSearchContentKind.Text);
+
+            if (match.ContentKind == QueryMatchContentKind.AppManagedText &&
+                match is AppManagedTextQueryMatch textMatch)
+            {
+                result.TextOffset = textMatch.TextOffset;
+                result.TextLength = textMatch.TextLength;
+            }
+
+            results.Add(result);
+        }
+
+        return results;
+    }
+
+    private static IReadOnlyList<SemanticSearchResult> ConvertImageMatches(IReadOnlyList<ImageQueryMatch> matches)
+    {
+        var results = new List<SemanticSearchResult>();
+
+        foreach (var match in matches)
+        {
+            var result = new SemanticSearchResult(match.ContentId, SemanticSearchContentKind.Image);
+            results.Add(result);
+        }
+
+        return results;
+    }
+
+    private void ThrowIfDisposed()
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+    }
+
+    private void ThrowIfNotInitialized()
+    {
+        if (_indexer == null)
+        {
+            throw new InvalidOperationException("Search engine is not initialized. Call InitializeAsync() first.");
+        }
+    }
+}

src/common/Common.Search/SemanticSearch/SemanticSearchMatchScope.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// Specifies the scope for semantic search matching.
+/// </summary>
+public enum SemanticSearchMatchScope
+{
+    /// <summary>
+    /// No constraints, uses both Lexical and Semantic matching.
+    /// </summary>
+    Unconstrained,
+
+    /// <summary>
+    /// Restrict matching to a specific region.
+    /// </summary>
+    Region,
+
+    /// <summary>
+    /// Restrict matching to a single content item.
+    /// </summary>
+    ContentItem,
+}

src/common/Common.Search/SemanticSearch/SemanticSearchOptions.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// Options for configuring semantic search queries.
+/// </summary>
+public class SemanticSearchOptions
+{
+    /// <summary>
+    /// Gets or sets the language for the search query (e.g., "en-US").
+    /// </summary>
+    public string? Language { get; set; }
+
+    /// <summary>
+    /// Gets or sets the match scope for the search.
+    /// </summary>
+    public SemanticSearchMatchScope MatchScope { get; set; } = SemanticSearchMatchScope.Unconstrained;
+
+    /// <summary>
+    /// Gets or sets the text match type for lexical matching.
+    /// </summary>
+    public SemanticSearchTextMatchType TextMatchType { get; set; } = SemanticSearchTextMatchType.Fuzzy;
+
+    /// <summary>
+    /// Gets or sets the maximum number of results to return.
+    /// </summary>
+    public int MaxResults { get; set; } = 10;
+}

src/common/Common.Search/SemanticSearch/SemanticSearchResult.cs

@@ -0,0 +1,42 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// Represents a search result from the semantic search engine.
+/// </summary>
+public class SemanticSearchResult
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SemanticSearchResult"/> class.
+    /// </summary>
+    /// <param name="contentId">The unique identifier of the matched content.</param>
+    /// <param name="contentKind">The kind of content matched (text or image).</param>
+    public SemanticSearchResult(string contentId, SemanticSearchContentKind contentKind)
+    {
+        ContentId = contentId;
+        ContentKind = contentKind;
+    }
+
+    /// <summary>
+    /// Gets the unique identifier of the matched content.
+    /// </summary>
+    public string ContentId { get; }
+
+    /// <summary>
+    /// Gets the kind of content that was matched.
+    /// </summary>
+    public SemanticSearchContentKind ContentKind { get; }
+
+    /// <summary>
+    /// Gets or sets the text offset where the match was found (for text matches only).
+    /// </summary>
+    public int TextOffset { get; set; }
+
+    /// <summary>
+    /// Gets or sets the length of the matched text (for text matches only).
+    /// </summary>
+    public int TextLength { get; set; }
+}

src/common/Common.Search/SemanticSearch/SemanticSearchTextMatchType.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Common.Search.SemanticSearch;
+
+/// <summary>
+/// Specifies the type of text matching for lexical searches.
+/// </summary>
+public enum SemanticSearchTextMatchType
+{
+    /// <summary>
+    /// Fuzzy matching allows spelling errors and approximate words.
+    /// </summary>
+    Fuzzy,
+
+    /// <summary>
+    /// Exact matching requires exact text matches.
+    /// </summary>
+    Exact,
+}

src/common/Common.UI/SettingsDeepLink.cs

@@ -45,6 +45,7 @@ namespace Common.UI
             NewPlus,
             CmdPal,
             ZoomIt,
+            PowerDisplay,
         }
 
         private static string SettingsWindowNameToString(SettingsWindow value)
@@ -115,6 +116,8 @@ namespace Common.UI
                     return "CmdPal";
                 case SettingsWindow.ZoomIt:
                     return "ZoomIt";
+                case SettingsWindow.PowerDisplay:
+                    return "PowerDisplay";
                 default:
                     {
                         return string.Empty;

src/common/GPOWrapper/GPOWrapper.cpp

@@ -32,6 +32,10 @@ namespace winrt::PowerToys::GPOWrapper::implementation
     {
         return static_cast<GpoRuleConfigured>(powertoys_gpo::getConfiguredLightSwitchEnabledValue());
     }
+    GpoRuleConfigured GPOWrapper::GetConfiguredPowerDisplayEnabledValue()
+    {
+        return static_cast<GpoRuleConfigured>(powertoys_gpo::getConfiguredPowerDisplayEnabledValue());
+    }
     GpoRuleConfigured GPOWrapper::GetConfiguredFancyZonesEnabledValue()
     {
         return static_cast<GpoRuleConfigured>(powertoys_gpo::getConfiguredFancyZonesEnabledValue());

src/common/GPOWrapper/GPOWrapper.h

@@ -14,6 +14,7 @@ namespace winrt::PowerToys::GPOWrapper::implementation
         static GpoRuleConfigured GetConfiguredColorPickerEnabledValue();
         static GpoRuleConfigured GetConfiguredCropAndLockEnabledValue();
         static GpoRuleConfigured GetConfiguredLightSwitchEnabledValue();
+        static GpoRuleConfigured GetConfiguredPowerDisplayEnabledValue();
         static GpoRuleConfigured GetConfiguredFancyZonesEnabledValue();
         static GpoRuleConfigured GetConfiguredFileLocksmithEnabledValue();
         static GpoRuleConfigured GetConfiguredSvgPreviewEnabledValue();

src/common/GPOWrapper/GPOWrapper.idl

@@ -18,6 +18,7 @@ namespace PowerToys
             static GpoRuleConfigured GetConfiguredColorPickerEnabledValue();
             static GpoRuleConfigured GetConfiguredCropAndLockEnabledValue();
             static GpoRuleConfigured GetConfiguredLightSwitchEnabledValue();
+            static GpoRuleConfigured GetConfiguredPowerDisplayEnabledValue();
             static GpoRuleConfigured GetConfiguredFancyZonesEnabledValue();
             static GpoRuleConfigured GetConfiguredFileLocksmithEnabledValue();
             static GpoRuleConfigured GetConfiguredSvgPreviewEnabledValue();

src/common/ManagedCommon/ModuleType.cs

@@ -30,6 +30,7 @@ namespace ManagedCommon
         PowerRename,
         PowerLauncher,
         PowerAccent,
+        PowerDisplay,
         RegistryPreview,
         MeasureTool,
         ShortcutGuide,

src/common/UnitTests-CommonUtils/AppMutex.Tests.cpp

@@ -0,0 +1,120 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <appMutex.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(AppMutexTests)
+    {
+    public:
+        TEST_METHOD(CreateAppMutex_ValidName_ReturnsHandle)
+        {
+            std::wstring mutexName = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_1";
+            auto handle = createAppMutex(mutexName);
+            Assert::IsNotNull(handle.get());
+        }
+
+        TEST_METHOD(CreateAppMutex_SameName_ReturnsExistingHandle)
+        {
+            std::wstring mutexName = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_2";
+
+            auto handle1 = createAppMutex(mutexName);
+            Assert::IsNotNull(handle1.get());
+
+            auto handle2 = createAppMutex(mutexName);
+            Assert::IsNull(handle2.get());
+        }
+
+        TEST_METHOD(CreateAppMutex_DifferentNames_ReturnsDifferentHandles)
+        {
+            std::wstring mutexName1 = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_A";
+            std::wstring mutexName2 = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_B";
+
+            auto handle1 = createAppMutex(mutexName1);
+            auto handle2 = createAppMutex(mutexName2);
+
+            Assert::IsNotNull(handle1.get());
+            Assert::IsNotNull(handle2.get());
+            Assert::AreNotEqual(handle1.get(), handle2.get());
+        }
+
+        TEST_METHOD(CreateAppMutex_EmptyName_ReturnsHandle)
+        {
+            // Empty name creates unnamed mutex
+            auto handle = createAppMutex(L"");
+            // CreateMutexW with empty string should still work
+            Assert::IsTrue(true);
+            // Test passes regardless - just checking it doesn't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(CreateAppMutex_LongName_ReturnsHandle)
+        {
+            // Create a long mutex name
+            std::wstring mutexName = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_";
+            for (int i = 0; i < 50; ++i)
+            {
+                mutexName += L"LongNameSegment";
+            }
+
+            auto handle = createAppMutex(mutexName);
+            // Long names might fail, but shouldn't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(CreateAppMutex_SpecialCharacters_ReturnsHandle)
+        {
+            std::wstring mutexName = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_Special!@#$%";
+
+            auto handle = createAppMutex(mutexName);
+            // Some special characters might not be valid in mutex names
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(CreateAppMutex_GlobalPrefix_ReturnsHandle)
+        {
+            // Global prefix for cross-session mutex
+            std::wstring mutexName = L"Global\\TestMutex_" + std::to_wstring(GetCurrentProcessId());
+
+            auto handle = createAppMutex(mutexName);
+            // Might require elevation, but shouldn't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(CreateAppMutex_LocalPrefix_ReturnsHandle)
+        {
+            std::wstring mutexName = L"Local\\TestMutex_" + std::to_wstring(GetCurrentProcessId());
+
+            auto handle = createAppMutex(mutexName);
+            Assert::IsNotNull(handle.get());
+        }
+
+        TEST_METHOD(CreateAppMutex_MultipleCalls_AllSucceed)
+        {
+            std::vector<wil::unique_mutex_nothrow> handles;
+            for (int i = 0; i < 10; ++i)
+            {
+                std::wstring mutexName = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) +
+                                         L"_Multi_" + std::to_wstring(i);
+                auto handle = createAppMutex(mutexName);
+                Assert::IsNotNull(handle.get());
+                handles.push_back(std::move(handle));
+            }
+        }
+
+        TEST_METHOD(CreateAppMutex_ReleaseAndRecreate_Works)
+        {
+            std::wstring mutexName = L"TestMutex_" + std::to_wstring(GetCurrentProcessId()) + L"_Recreate";
+
+            auto handle1 = createAppMutex(mutexName);
+            Assert::IsNotNull(handle1.get());
+            handle1.reset();
+
+            // After closing, should be able to create again
+            auto handle2 = createAppMutex(mutexName);
+            Assert::IsNotNull(handle2.get());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ColorUtils.Tests.cpp

@@ -0,0 +1,220 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <color.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ColorUtilsTests)
+    {
+    public:
+        // checkValidRGB tests
+        TEST_METHOD(CheckValidRGB_ValidBlack_ReturnsTrue)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#000000", &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0), r);
+            Assert::AreEqual(static_cast<uint8_t>(0), g);
+            Assert::AreEqual(static_cast<uint8_t>(0), b);
+        }
+
+        TEST_METHOD(CheckValidRGB_ValidWhite_ReturnsTrue)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#FFFFFF", &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(255), r);
+            Assert::AreEqual(static_cast<uint8_t>(255), g);
+            Assert::AreEqual(static_cast<uint8_t>(255), b);
+        }
+
+        TEST_METHOD(CheckValidRGB_ValidRed_ReturnsTrue)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#FF0000", &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(255), r);
+            Assert::AreEqual(static_cast<uint8_t>(0), g);
+            Assert::AreEqual(static_cast<uint8_t>(0), b);
+        }
+
+        TEST_METHOD(CheckValidRGB_ValidGreen_ReturnsTrue)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#00FF00", &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0), r);
+            Assert::AreEqual(static_cast<uint8_t>(255), g);
+            Assert::AreEqual(static_cast<uint8_t>(0), b);
+        }
+
+        TEST_METHOD(CheckValidRGB_ValidBlue_ReturnsTrue)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#0000FF", &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0), r);
+            Assert::AreEqual(static_cast<uint8_t>(0), g);
+            Assert::AreEqual(static_cast<uint8_t>(255), b);
+        }
+
+        TEST_METHOD(CheckValidRGB_ValidMixed_ReturnsTrue)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#AB12CD", &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0xAB), r);
+            Assert::AreEqual(static_cast<uint8_t>(0x12), g);
+            Assert::AreEqual(static_cast<uint8_t>(0xCD), b);
+        }
+
+        TEST_METHOD(CheckValidRGB_MissingHash_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"FFFFFF", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidRGB_TooShort_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#FFF", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidRGB_TooLong_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#FFFFFFFF", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidRGB_InvalidChars_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#GGHHII", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidRGB_LowercaseInvalid_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#ffffff", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidRGB_EmptyString_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidRGB_OnlyHash_ReturnsFalse)
+        {
+            uint8_t r, g, b;
+            bool result = checkValidRGB(L"#", &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        // checkValidARGB tests
+        TEST_METHOD(CheckValidARGB_ValidBlackOpaque_ReturnsTrue)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#FF000000", &a, &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(255), a);
+            Assert::AreEqual(static_cast<uint8_t>(0), r);
+            Assert::AreEqual(static_cast<uint8_t>(0), g);
+            Assert::AreEqual(static_cast<uint8_t>(0), b);
+        }
+
+        TEST_METHOD(CheckValidARGB_ValidWhiteOpaque_ReturnsTrue)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#FFFFFFFF", &a, &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(255), a);
+            Assert::AreEqual(static_cast<uint8_t>(255), r);
+            Assert::AreEqual(static_cast<uint8_t>(255), g);
+            Assert::AreEqual(static_cast<uint8_t>(255), b);
+        }
+
+        TEST_METHOD(CheckValidARGB_ValidTransparent_ReturnsTrue)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#00FFFFFF", &a, &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0), a);
+            Assert::AreEqual(static_cast<uint8_t>(255), r);
+            Assert::AreEqual(static_cast<uint8_t>(255), g);
+            Assert::AreEqual(static_cast<uint8_t>(255), b);
+        }
+
+        TEST_METHOD(CheckValidARGB_ValidSemiTransparent_ReturnsTrue)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#80FF0000", &a, &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0x80), a);
+            Assert::AreEqual(static_cast<uint8_t>(255), r);
+            Assert::AreEqual(static_cast<uint8_t>(0), g);
+            Assert::AreEqual(static_cast<uint8_t>(0), b);
+        }
+
+        TEST_METHOD(CheckValidARGB_ValidMixed_ReturnsTrue)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#12345678", &a, &r, &g, &b);
+            Assert::IsTrue(result);
+            Assert::AreEqual(static_cast<uint8_t>(0x12), a);
+            Assert::AreEqual(static_cast<uint8_t>(0x34), r);
+            Assert::AreEqual(static_cast<uint8_t>(0x56), g);
+            Assert::AreEqual(static_cast<uint8_t>(0x78), b);
+        }
+
+        TEST_METHOD(CheckValidARGB_MissingHash_ReturnsFalse)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"FFFFFFFF", &a, &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidARGB_TooShort_ReturnsFalse)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#FFFFFF", &a, &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidARGB_TooLong_ReturnsFalse)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#FFFFFFFFFF", &a, &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidARGB_InvalidChars_ReturnsFalse)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#GGHHIIJJ", &a, &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidARGB_LowercaseInvalid_ReturnsFalse)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"#ffffffff", &a, &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(CheckValidARGB_EmptyString_ReturnsFalse)
+        {
+            uint8_t a, r, g, b;
+            bool result = checkValidARGB(L"", &a, &r, &g, &b);
+            Assert::IsFalse(result);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ComObjectFactory.Tests.cpp

@@ -0,0 +1,228 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <com_object_factory.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    // Test COM object for testing the factory
+    class TestComObject : public IUnknown
+    {
+    public:
+        TestComObject() : m_refCount(1) {}
+
+        HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void** ppvObject) override
+        {
+            if (riid == IID_IUnknown)
+            {
+                *ppvObject = static_cast<IUnknown*>(this);
+                AddRef();
+                return S_OK;
+            }
+            *ppvObject = nullptr;
+            return E_NOINTERFACE;
+        }
+
+        ULONG STDMETHODCALLTYPE AddRef() override
+        {
+            return InterlockedIncrement(&m_refCount);
+        }
+
+        ULONG STDMETHODCALLTYPE Release() override
+        {
+            ULONG count = InterlockedDecrement(&m_refCount);
+            if (count == 0)
+            {
+                delete this;
+            }
+            return count;
+        }
+
+    private:
+        LONG m_refCount;
+    };
+
+    TEST_CLASS(ComObjectFactoryTests)
+    {
+    public:
+        TEST_METHOD(ComObjectFactory_Construction_DoesNotCrash)
+        {
+            com_object_factory<TestComObject> factory;
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(ComObjectFactory_QueryInterface_IUnknown_Succeeds)
+        {
+            com_object_factory<TestComObject> factory;
+            IUnknown* pUnknown = nullptr;
+
+            HRESULT hr = factory.QueryInterface(IID_IUnknown, reinterpret_cast<void**>(&pUnknown));
+
+            Assert::AreEqual(S_OK, hr);
+            Assert::IsNotNull(pUnknown);
+
+            if (pUnknown)
+            {
+                pUnknown->Release();
+            }
+        }
+
+        TEST_METHOD(ComObjectFactory_QueryInterface_IClassFactory_Succeeds)
+        {
+            com_object_factory<TestComObject> factory;
+            IClassFactory* pFactory = nullptr;
+
+            HRESULT hr = factory.QueryInterface(IID_IClassFactory, reinterpret_cast<void**>(&pFactory));
+
+            Assert::AreEqual(S_OK, hr);
+            Assert::IsNotNull(pFactory);
+
+            if (pFactory)
+            {
+                pFactory->Release();
+            }
+        }
+
+        TEST_METHOD(ComObjectFactory_QueryInterface_InvalidInterface_Fails)
+        {
+            com_object_factory<TestComObject> factory;
+            void* pInterface = nullptr;
+
+            // Random GUID that we don't support
+            GUID randomGuid = { 0x12345678, 0x1234, 0x1234, { 0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xF0 } };
+            HRESULT hr = factory.QueryInterface(randomGuid, &pInterface);
+
+            Assert::AreEqual(E_NOINTERFACE, hr);
+            Assert::IsNull(pInterface);
+        }
+
+        TEST_METHOD(ComObjectFactory_AddRef_IncreasesRefCount)
+        {
+            com_object_factory<TestComObject> factory;
+
+            ULONG count1 = factory.AddRef();
+            ULONG count2 = factory.AddRef();
+
+            Assert::IsTrue(count2 > count1);
+
+            // Clean up
+            factory.Release();
+            factory.Release();
+        }
+
+        TEST_METHOD(ComObjectFactory_Release_DecreasesRefCount)
+        {
+            com_object_factory<TestComObject> factory;
+
+            factory.AddRef();
+            factory.AddRef();
+            ULONG count1 = factory.Release();
+            ULONG count2 = factory.Release();
+
+            Assert::IsTrue(count2 < count1);
+        }
+
+        TEST_METHOD(ComObjectFactory_CreateInstance_NoAggregation_Succeeds)
+        {
+            com_object_factory<TestComObject> factory;
+            IUnknown* pObj = nullptr;
+
+            HRESULT hr = factory.CreateInstance(nullptr, IID_IUnknown, reinterpret_cast<void**>(&pObj));
+
+            Assert::AreEqual(S_OK, hr);
+            Assert::IsNotNull(pObj);
+
+            if (pObj)
+            {
+                pObj->Release();
+            }
+        }
+
+        TEST_METHOD(ComObjectFactory_CreateInstance_WithAggregation_Fails)
+        {
+            com_object_factory<TestComObject> factory;
+            TestComObject outer;
+            IUnknown* pObj = nullptr;
+
+            // Aggregation should fail for our simple test object
+            HRESULT hr = factory.CreateInstance(&outer, IID_IUnknown, reinterpret_cast<void**>(&pObj));
+
+            Assert::AreEqual(CLASS_E_NOAGGREGATION, hr);
+            Assert::IsNull(pObj);
+        }
+
+        TEST_METHOD(ComObjectFactory_CreateInstance_NullOutput_Fails)
+        {
+            com_object_factory<TestComObject> factory;
+
+            HRESULT hr = factory.CreateInstance(nullptr, IID_IUnknown, nullptr);
+
+            Assert::AreEqual(E_POINTER, hr);
+        }
+
+        TEST_METHOD(ComObjectFactory_LockServer_Lock_Succeeds)
+        {
+            com_object_factory<TestComObject> factory;
+
+            HRESULT hr = factory.LockServer(TRUE);
+            Assert::AreEqual(S_OK, hr);
+
+            // Unlock
+            factory.LockServer(FALSE);
+        }
+
+        TEST_METHOD(ComObjectFactory_LockServer_Unlock_Succeeds)
+        {
+            com_object_factory<TestComObject> factory;
+
+            factory.LockServer(TRUE);
+            HRESULT hr = factory.LockServer(FALSE);
+
+            Assert::AreEqual(S_OK, hr);
+        }
+
+        TEST_METHOD(ComObjectFactory_LockServer_MultipleLocks_Work)
+        {
+            com_object_factory<TestComObject> factory;
+
+            factory.LockServer(TRUE);
+            factory.LockServer(TRUE);
+            factory.LockServer(TRUE);
+
+            factory.LockServer(FALSE);
+            factory.LockServer(FALSE);
+            HRESULT hr = factory.LockServer(FALSE);
+
+            Assert::AreEqual(S_OK, hr);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(ComObjectFactory_ConcurrentCreateInstance_Works)
+        {
+            com_object_factory<TestComObject> factory;
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&factory, &successCount]() {
+                    IUnknown* pObj = nullptr;
+                    HRESULT hr = factory.CreateInstance(nullptr, IID_IUnknown, reinterpret_cast<void**>(&pObj));
+                    if (SUCCEEDED(hr) && pObj)
+                    {
+                        successCount++;
+                        pObj->Release();
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(10, successCount.load());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Elevation.Tests.cpp

@@ -0,0 +1,146 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <elevation.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ElevationTests)
+    {
+    public:
+        // is_process_elevated tests
+        TEST_METHOD(IsProcessElevated_ReturnsBoolean)
+        {
+            bool result = is_process_elevated(false);
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsProcessElevated_CachedValue_ReturnsSameResult)
+        {
+            bool result1 = is_process_elevated(true);
+            bool result2 = is_process_elevated(true);
+
+            // Cached value should be consistent
+            Assert::AreEqual(result1, result2);
+        }
+
+        TEST_METHOD(IsProcessElevated_UncachedValue_ReturnsBoolean)
+        {
+            bool result = is_process_elevated(false);
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsProcessElevated_CachedAndUncached_AreConsistent)
+        {
+            // Both should return the same value for the same process
+            bool cached = is_process_elevated(true);
+            bool uncached = is_process_elevated(false);
+
+            Assert::AreEqual(cached, uncached);
+        }
+
+        // check_user_is_admin tests
+        TEST_METHOD(CheckUserIsAdmin_ReturnsBoolean)
+        {
+            bool result = check_user_is_admin();
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(CheckUserIsAdmin_ConsistentResults)
+        {
+            bool result1 = check_user_is_admin();
+            bool result2 = check_user_is_admin();
+            bool result3 = check_user_is_admin();
+
+            Assert::AreEqual(result1, result2);
+            Assert::AreEqual(result2, result3);
+        }
+
+        // Relationship between elevation and admin
+        TEST_METHOD(ElevationAndAdmin_Relationship)
+        {
+            bool elevated = is_process_elevated(false);
+            bool admin = check_user_is_admin();
+            (void)admin;
+
+            // If elevated, user should typically be admin
+            // But user can be admin without process being elevated
+            if (elevated)
+            {
+                // Elevated process usually means admin user
+                // (though there are edge cases)
+            }
+            // Just verify both functions return without crashing
+            Assert::IsTrue(true);
+        }
+
+        // IsProcessOfWindowElevated tests
+        TEST_METHOD(IsProcessOfWindowElevated_DesktopWindow_ReturnsBoolean)
+        {
+            HWND desktop = GetDesktopWindow();
+            if (desktop)
+            {
+                bool result = IsProcessOfWindowElevated(desktop);
+                Assert::IsTrue(result == true || result == false);
+            }
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(IsProcessOfWindowElevated_InvalidHwnd_DoesNotCrash)
+        {
+            bool result = IsProcessOfWindowElevated(nullptr);
+            // Should handle null HWND gracefully
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        // ProcessInfo struct tests
+        TEST_METHOD(ProcessInfo_DefaultConstruction)
+        {
+            ProcessInfo info{};
+            Assert::AreEqual(static_cast<DWORD>(0), info.processID);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(IsProcessElevated_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        is_process_elevated(j % 2 == 0);
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+
+        // Performance of cached value
+        TEST_METHOD(IsProcessElevated_CachedPerformance)
+        {
+            auto start = std::chrono::high_resolution_clock::now();
+
+            for (int i = 0; i < 10000; ++i)
+            {
+                is_process_elevated(true);
+            }
+
+            auto end = std::chrono::high_resolution_clock::now();
+            auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
+
+            // Cached calls should be very fast
+            Assert::IsTrue(duration.count() < 1000);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ExcludedApps.Tests.cpp

@@ -0,0 +1,182 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <excluded_apps.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ExcludedAppsTests)
+    {
+    public:
+        // find_app_name_in_path tests
+        TEST_METHOD(FindAppNameInPath_ExactMatch_ReturnsTrue)
+        {
+            std::wstring path = L"C:\\Program Files\\App\\notepad.exe";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            Assert::IsTrue(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_NoMatch_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\Program Files\\App\\notepad.exe";
+            std::vector<std::wstring> apps = { L"calc.exe" };
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_MultipleApps_FindsMatch)
+        {
+            std::wstring path = L"C:\\Program Files\\App\\notepad.exe";
+            std::vector<std::wstring> apps = { L"calc.exe", L"notepad.exe", L"word.exe" };
+            Assert::IsTrue(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_EmptyPath_ReturnsFalse)
+        {
+            std::wstring path = L"";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_EmptyApps_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\Program Files\\App\\notepad.exe";
+            std::vector<std::wstring> apps = {};
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_PartialMatchInFolder_ReturnsFalse)
+        {
+            // "notepad" appears in folder name but not as the exe name
+            std::wstring path = L"C:\\notepad\\other.exe";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_CaseSensitive_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\Program Files\\App\\NOTEPAD.EXE";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            // The function does rfind which is case-sensitive
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_MatchWithDifferentExtension_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\Program Files\\App\\notepad.com";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_MatchAtEndOfPath_ReturnsTrue)
+        {
+            std::wstring path = L"C:\\Windows\\System32\\notepad.exe";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            Assert::IsTrue(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_UNCPath_Works)
+        {
+            std::wstring path = L"\\\\server\\share\\folder\\app.exe";
+            std::vector<std::wstring> apps = { L"app.exe" };
+            Assert::IsTrue(find_app_name_in_path(path, apps));
+        }
+
+        // find_folder_in_path tests
+        TEST_METHOD(FindFolderInPath_FolderExists_ReturnsTrue)
+        {
+            std::wstring path = L"C:\\Program Files\\MyApp\\app.exe";
+            std::vector<std::wstring> folders = { L"Program Files" };
+            Assert::IsTrue(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_FolderNotExists_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\Windows\\System32\\app.exe";
+            std::vector<std::wstring> folders = { L"Program Files" };
+            Assert::IsFalse(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_MultipleFolders_FindsMatch)
+        {
+            std::wstring path = L"C:\\Windows\\System32\\app.exe";
+            std::vector<std::wstring> folders = { L"Program Files", L"System32", L"Users" };
+            Assert::IsTrue(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_EmptyPath_ReturnsFalse)
+        {
+            std::wstring path = L"";
+            std::vector<std::wstring> folders = { L"Windows" };
+            Assert::IsFalse(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_EmptyFolders_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\Windows\\app.exe";
+            std::vector<std::wstring> folders = {};
+            Assert::IsFalse(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_PartialMatch_ReturnsTrue)
+        {
+            // find_folder_in_path uses rfind which finds substrings
+            std::wstring path = L"C:\\Windows\\System32\\app.exe";
+            std::vector<std::wstring> folders = { L"System" };
+            Assert::IsTrue(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_NestedFolder_ReturnsTrue)
+        {
+            std::wstring path = L"C:\\Program Files\\Company\\Product\\bin\\app.exe";
+            std::vector<std::wstring> folders = { L"Product" };
+            Assert::IsTrue(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_RootDrive_ReturnsTrue)
+        {
+            std::wstring path = L"C:\\folder\\app.exe";
+            std::vector<std::wstring> folders = { L"C:\\" };
+            Assert::IsTrue(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_UNCPath_Works)
+        {
+            std::wstring path = L"\\\\server\\share\\folder\\app.exe";
+            std::vector<std::wstring> folders = { L"share" };
+            Assert::IsTrue(find_folder_in_path(path, folders));
+        }
+
+        TEST_METHOD(FindFolderInPath_CaseSensitive_ReturnsFalse)
+        {
+            std::wstring path = L"C:\\WINDOWS\\app.exe";
+            std::vector<std::wstring> folders = { L"windows" };
+            // rfind is case-sensitive
+            Assert::IsFalse(find_folder_in_path(path, folders));
+        }
+
+        // Edge case tests
+        TEST_METHOD(FindAppNameInPath_AppNameInMiddleOfPath_HandlesCorrectly)
+        {
+            // The app name appears both in folder and as filename
+            std::wstring path = L"C:\\notepad\\bin\\notepad.exe";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            Assert::IsTrue(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindAppNameInPath_JustFilename_ReturnsFalse)
+        {
+            std::wstring path = L"notepad.exe";
+            std::vector<std::wstring> apps = { L"notepad.exe" };
+            // find_app_name_in_path expects a path separator to validate the executable segment
+            Assert::IsFalse(find_app_name_in_path(path, apps));
+        }
+
+        TEST_METHOD(FindFolderInPath_JustFilename_ReturnsFalse)
+        {
+            std::wstring path = L"app.exe";
+            std::vector<std::wstring> folders = { L"Windows" };
+            Assert::IsFalse(find_folder_in_path(path, folders));
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Exec.Tests.cpp

@@ -0,0 +1,148 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <exec.h>
+#include <cctype>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ExecTests)
+    {
+    public:
+        TEST_METHOD(ExecAndReadOutput_EchoCommand_ReturnsOutput)
+        {
+            auto result = exec_and_read_output(L"cmd /c echo hello", 5000);
+
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+            // Output should contain "hello"
+            Assert::IsTrue(result->find("hello") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_WhereCommand_ReturnsPath)
+        {
+            auto result = exec_and_read_output(L"where cmd", 5000);
+
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+            // Should contain path to cmd.exe
+            Assert::IsTrue(result->find("cmd") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_DirCommand_ReturnsListing)
+        {
+            auto result = exec_and_read_output(L"cmd /c dir /b C:\\Windows", 5000);
+
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+            // Should contain some common Windows folder names
+            std::string output = *result;
+            std::transform(output.begin(), output.end(), output.begin(), [](unsigned char ch) { return static_cast<char>(std::tolower(ch)); });
+            Assert::IsTrue(output.find("system32") != std::string::npos ||
+                          output.find("system") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_InvalidCommand_ReturnsEmptyOrError)
+        {
+            auto result = exec_and_read_output(L"nonexistentcommand12345", 5000);
+
+            // Invalid command should either return nullopt or an error message
+            Assert::IsTrue(!result.has_value() || result->empty() ||
+                          result->find("not recognized") != std::string::npos ||
+                          result->find("error") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_EmptyCommand_DoesNotCrash)
+        {
+            auto result = exec_and_read_output(L"", 5000);
+            // Should handle empty command gracefully
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_TimeoutExpires_ReturnsAvailableOutput)
+        {
+            // Use a command that produces output slowly
+            // ping localhost will run for a while
+            auto start = std::chrono::steady_clock::now();
+
+            // Very short timeout
+            auto result = exec_and_read_output(L"ping localhost -n 10", 100);
+
+            auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::chrono::steady_clock::now() - start);
+
+            // Should return within reasonable time
+            Assert::IsTrue(elapsed.count() < 5000);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_MultilineOutput_PreservesLines)
+        {
+            auto result = exec_and_read_output(L"cmd /c \"echo line1 & echo line2 & echo line3\"", 5000);
+
+            Assert::IsTrue(result.has_value());
+            // Should contain multiple lines
+            Assert::IsTrue(result->find("line1") != std::string::npos);
+            Assert::IsTrue(result->find("line2") != std::string::npos);
+            Assert::IsTrue(result->find("line3") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_UnicodeOutput_Works)
+        {
+            // Echo a simple ASCII string (Unicode test depends on system codepage)
+            auto result = exec_and_read_output(L"cmd /c echo test123", 5000);
+
+            Assert::IsTrue(result.has_value());
+            Assert::IsTrue(result->find("test123") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_LongTimeout_Works)
+        {
+            auto result = exec_and_read_output(L"cmd /c echo test", 60000);
+
+            Assert::IsTrue(result.has_value());
+            Assert::IsTrue(result->find("test") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_QuotedArguments_Work)
+        {
+            auto result = exec_and_read_output(L"cmd /c echo \"hello world\"", 5000);
+
+            Assert::IsTrue(result.has_value());
+            Assert::IsTrue(result->find("hello") != std::string::npos);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_EnvironmentVariable_Expanded)
+        {
+            auto result = exec_and_read_output(L"cmd /c echo %USERNAME%", 5000);
+
+            Assert::IsTrue(result.has_value());
+            // Should not contain the literal %USERNAME% but the actual username
+            // Or if not expanded, still should not crash
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(ExecAndReadOutput_ExitCode_CommandFails)
+        {
+            // Command that exits with error
+            auto result = exec_and_read_output(L"cmd /c exit 1", 5000);
+
+            // Should still return something (possibly empty)
+            // Just verify it doesn't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(ExecAndReadOutput_ZeroTimeout_DoesNotHang)
+        {
+            auto start = std::chrono::steady_clock::now();
+
+            auto result = exec_and_read_output(L"cmd /c echo test", 0);
+
+            auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::chrono::steady_clock::now() - start);
+
+            // Should complete quickly with zero timeout
+            Assert::IsTrue(elapsed.count() < 5000);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/GameMode.Tests.cpp

@@ -0,0 +1,68 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <game_mode.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(GameModeTests)
+    {
+    public:
+        TEST_METHOD(DetectGameMode_ReturnsBoolean)
+        {
+            // This function queries Windows game mode status
+            bool result = detect_game_mode();
+
+            // Result depends on current system state, but should be a valid boolean
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(DetectGameMode_ConsistentResults)
+        {
+            // Multiple calls should return consistent results (unless game mode changes)
+            bool result1 = detect_game_mode();
+            bool result2 = detect_game_mode();
+            bool result3 = detect_game_mode();
+
+            // Results should be consistent across rapid calls
+            Assert::AreEqual(result1, result2);
+            Assert::AreEqual(result2, result3);
+        }
+
+        TEST_METHOD(DetectGameMode_DoesNotCrash)
+        {
+            // Call multiple times to ensure no crash or memory leak
+            for (int i = 0; i < 100; ++i)
+            {
+                detect_game_mode();
+            }
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(DetectGameMode_ThreadSafe)
+        {
+            // Test that calling from multiple threads is safe
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        detect_game_mode();
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Gpo.Tests.cpp

@@ -0,0 +1,218 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <gpo.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+using namespace powertoys_gpo;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(GpoTests)
+    {
+    public:
+        // Helper to check if result is a valid gpo_rule_configured_t value
+        static constexpr bool IsValidGpoResult(gpo_rule_configured_t result)
+        {
+            return result == gpo_rule_configured_wrong_value ||
+                   result == gpo_rule_configured_unavailable ||
+                   result == gpo_rule_configured_not_configured ||
+                   result == gpo_rule_configured_disabled ||
+                   result == gpo_rule_configured_enabled;
+        }
+
+        // gpo_rule_configured_t enum tests
+        TEST_METHOD(GpoRuleConfigured_EnumValues_AreDistinct)
+        {
+            Assert::AreNotEqual(static_cast<int>(gpo_rule_configured_not_configured),
+                               static_cast<int>(gpo_rule_configured_enabled));
+            Assert::AreNotEqual(static_cast<int>(gpo_rule_configured_enabled),
+                               static_cast<int>(gpo_rule_configured_disabled));
+            Assert::AreNotEqual(static_cast<int>(gpo_rule_configured_not_configured),
+                               static_cast<int>(gpo_rule_configured_disabled));
+        }
+
+        // getConfiguredValue tests
+        TEST_METHOD(GetConfiguredValue_NonExistentKey_ReturnsNotConfigured)
+        {
+            auto result = getConfiguredValue(L"NonExistentPolicyValue12345");
+            Assert::IsTrue(result == gpo_rule_configured_not_configured ||
+                          result == gpo_rule_configured_unavailable);
+        }
+
+        // Utility enabled getters - these all follow the same pattern
+        TEST_METHOD(GetAllowExperimentationValue_ReturnsValidState)
+        {
+            auto result = getAllowExperimentationValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredAlwaysOnTopEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredAlwaysOnTopEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredAwakeEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredAwakeEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredColorPickerEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredColorPickerEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredFancyZonesEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredFancyZonesEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredFileLocksmithEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredFileLocksmithEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredImageResizerEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredImageResizerEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredKeyboardManagerEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredKeyboardManagerEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredPowerRenameEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredPowerRenameEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredPowerLauncherEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredPowerLauncherEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredShortcutGuideEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredShortcutGuideEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredTextExtractorEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredTextExtractorEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredHostsFileEditorEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredHostsFileEditorEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredMousePointerCrosshairsEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredMousePointerCrosshairsEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredMouseHighlighterEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredMouseHighlighterEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredMouseJumpEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredMouseJumpEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredFindMyMouseEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredFindMyMouseEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredMouseWithoutBordersEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredMouseWithoutBordersEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredAdvancedPasteEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredAdvancedPasteEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredPeekEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredPeekEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredRegistryPreviewEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredRegistryPreviewEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredScreenRulerEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredScreenRulerEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredCropAndLockEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredCropAndLockEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        TEST_METHOD(GetConfiguredEnvironmentVariablesEnabledValue_ReturnsValidState)
+        {
+            auto result = getConfiguredEnvironmentVariablesEnabledValue();
+            Assert::IsTrue(IsValidGpoResult(result));
+        }
+
+        // All GPO functions should not crash
+        TEST_METHOD(AllGpoFunctions_DoNotCrash)
+        {
+            getAllowExperimentationValue();
+            getConfiguredAlwaysOnTopEnabledValue();
+            getConfiguredAwakeEnabledValue();
+            getConfiguredColorPickerEnabledValue();
+            getConfiguredFancyZonesEnabledValue();
+            getConfiguredFileLocksmithEnabledValue();
+            getConfiguredImageResizerEnabledValue();
+            getConfiguredKeyboardManagerEnabledValue();
+            getConfiguredPowerRenameEnabledValue();
+            getConfiguredPowerLauncherEnabledValue();
+            getConfiguredShortcutGuideEnabledValue();
+            getConfiguredTextExtractorEnabledValue();
+            getConfiguredHostsFileEditorEnabledValue();
+            getConfiguredMousePointerCrosshairsEnabledValue();
+            getConfiguredMouseHighlighterEnabledValue();
+            getConfiguredMouseJumpEnabledValue();
+            getConfiguredFindMyMouseEnabledValue();
+            getConfiguredMouseWithoutBordersEnabledValue();
+            getConfiguredAdvancedPasteEnabledValue();
+            getConfiguredPeekEnabledValue();
+            getConfiguredRegistryPreviewEnabledValue();
+            getConfiguredScreenRulerEnabledValue();
+            getConfiguredCropAndLockEnabledValue();
+            getConfiguredEnvironmentVariablesEnabledValue();
+
+            Assert::IsTrue(true);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/HDropIterator.Tests.cpp

@@ -0,0 +1,200 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <HDropIterator.h>
+#include <shlobj.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(HDropIteratorTests)
+    {
+    public:
+        // Helper to create a test HDROP structure
+        static HGLOBAL CreateTestHDrop(const std::vector<std::wstring>& files)
+        {
+            // Calculate required size
+            size_t size = sizeof(DROPFILES);
+            for (const auto& file : files)
+            {
+                size += (file.length() + 1) * sizeof(wchar_t);
+            }
+            size += sizeof(wchar_t); // Double null terminator
+
+            HGLOBAL hGlobal = GlobalAlloc(GHND, size);
+            if (!hGlobal) return nullptr;
+
+            DROPFILES* pDropFiles = static_cast<DROPFILES*>(GlobalLock(hGlobal));
+            if (!pDropFiles)
+            {
+                GlobalFree(hGlobal);
+                return nullptr;
+            }
+
+            pDropFiles->pFiles = sizeof(DROPFILES);
+            pDropFiles->fWide = TRUE;
+
+            wchar_t* pData = reinterpret_cast<wchar_t*>(reinterpret_cast<BYTE*>(pDropFiles) + sizeof(DROPFILES));
+            for (const auto& file : files)
+            {
+                wcscpy_s(pData, file.length() + 1, file.c_str());
+                pData += file.length() + 1;
+            }
+            *pData = L'\0'; // Double null terminator
+
+            GlobalUnlock(hGlobal);
+            return hGlobal;
+        }
+
+        TEST_METHOD(HDropIterator_EmptyDrop_IsDoneImmediately)
+        {
+            HGLOBAL hGlobal = CreateTestHDrop({});
+            if (!hGlobal)
+            {
+                Assert::IsTrue(true); // Skip if allocation failed
+                return;
+            }
+
+            STGMEDIUM medium = {};
+            medium.tymed = TYMED_HGLOBAL;
+            medium.hGlobal = hGlobal;
+
+            // Without a proper IDataObject, we can't fully test
+            // Just verify the class can be instantiated conceptually
+            GlobalFree(hGlobal);
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(HDropIterator_Iteration_Conceptual)
+        {
+            // This test verifies the concept of iteration
+            // Full integration testing requires a proper IDataObject
+
+            std::vector<std::wstring> testFiles = {
+                L"C:\\test\\file1.txt",
+                L"C:\\test\\file2.txt",
+                L"C:\\test\\file3.txt"
+            };
+
+            HGLOBAL hGlobal = CreateTestHDrop(testFiles);
+            if (!hGlobal)
+            {
+                Assert::IsTrue(true);
+                return;
+            }
+
+            // Verify we can create the HDROP structure
+            DROPFILES* pDropFiles = static_cast<DROPFILES*>(GlobalLock(hGlobal));
+            Assert::IsNotNull(pDropFiles);
+            Assert::IsTrue(pDropFiles->fWide);
+
+            GlobalUnlock(hGlobal);
+            GlobalFree(hGlobal);
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(HDropIterator_SingleFile_Works)
+        {
+            std::vector<std::wstring> testFiles = { L"C:\\test\\single.txt" };
+
+            HGLOBAL hGlobal = CreateTestHDrop(testFiles);
+            if (!hGlobal)
+            {
+                Assert::IsTrue(true);
+                return;
+            }
+
+            // Verify structure
+            DROPFILES* pDropFiles = static_cast<DROPFILES*>(GlobalLock(hGlobal));
+            Assert::IsNotNull(pDropFiles);
+
+            // Read back the file name
+            wchar_t* pData = reinterpret_cast<wchar_t*>(reinterpret_cast<BYTE*>(pDropFiles) + pDropFiles->pFiles);
+            Assert::AreEqual(std::wstring(L"C:\\test\\single.txt"), std::wstring(pData));
+
+            GlobalUnlock(hGlobal);
+            GlobalFree(hGlobal);
+        }
+
+        TEST_METHOD(HDropIterator_MultipleFiles_Structure)
+        {
+            std::vector<std::wstring> testFiles = {
+                L"C:\\file1.txt",
+                L"C:\\file2.txt",
+                L"C:\\file3.txt"
+            };
+
+            HGLOBAL hGlobal = CreateTestHDrop(testFiles);
+            if (!hGlobal)
+            {
+                Assert::IsTrue(true);
+                return;
+            }
+
+            DROPFILES* pDropFiles = static_cast<DROPFILES*>(GlobalLock(hGlobal));
+            Assert::IsNotNull(pDropFiles);
+
+            // Count files by iterating through null-terminated strings
+            wchar_t* pData = reinterpret_cast<wchar_t*>(reinterpret_cast<BYTE*>(pDropFiles) + pDropFiles->pFiles);
+            int count = 0;
+            while (*pData)
+            {
+                count++;
+                pData += wcslen(pData) + 1;
+            }
+
+            Assert::AreEqual(3, count);
+
+            GlobalUnlock(hGlobal);
+            GlobalFree(hGlobal);
+        }
+
+        TEST_METHOD(HDropIterator_UnicodeFilenames_Work)
+        {
+            std::vector<std::wstring> testFiles = {
+                L"C:\\test\\file.txt"
+            };
+
+            HGLOBAL hGlobal = CreateTestHDrop(testFiles);
+            if (!hGlobal)
+            {
+                Assert::IsTrue(true);
+                return;
+            }
+
+            DROPFILES* pDropFiles = static_cast<DROPFILES*>(GlobalLock(hGlobal));
+            Assert::IsTrue(pDropFiles->fWide == TRUE);
+
+            GlobalUnlock(hGlobal);
+            GlobalFree(hGlobal);
+        }
+
+        TEST_METHOD(HDropIterator_LongFilenames_Work)
+        {
+            std::wstring longPath = L"C:\\";
+            for (int i = 0; i < 20; ++i)
+            {
+                longPath += L"LongFolderName\\";
+            }
+            longPath += L"file.txt";
+
+            std::vector<std::wstring> testFiles = { longPath };
+
+            HGLOBAL hGlobal = CreateTestHDrop(testFiles);
+            if (!hGlobal)
+            {
+                Assert::IsTrue(true);
+                return;
+            }
+
+            DROPFILES* pDropFiles = static_cast<DROPFILES*>(GlobalLock(hGlobal));
+            Assert::IsNotNull(pDropFiles);
+
+            wchar_t* pData = reinterpret_cast<wchar_t*>(reinterpret_cast<BYTE*>(pDropFiles) + pDropFiles->pFiles);
+            Assert::AreEqual(longPath, std::wstring(pData));
+
+            GlobalUnlock(hGlobal);
+            GlobalFree(hGlobal);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/HttpClient.Tests.cpp

@@ -0,0 +1,152 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <HttpClient.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(HttpClientTests)
+    {
+    public:
+        // Note: Network tests may fail in offline environments
+        // These tests are designed to verify the API doesn't crash
+
+        TEST_METHOD(HttpClient_DefaultConstruction)
+        {
+            http::HttpClient client;
+            // Should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(HttpClient_Request_InvalidUri_ReturnsEmpty)
+        {
+            http::HttpClient client;
+
+            try
+            {
+                // Invalid URI should not crash, may throw or return empty
+                auto result = client.request(winrt::Windows::Foundation::Uri(L"invalid://not-a-valid-uri"));
+                // If we get here, result may be empty or contain error
+            }
+            catch (...)
+            {
+                // Exception is acceptable for invalid URI
+            }
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(HttpClient_Download_InvalidUri_DoesNotCrash)
+        {
+            http::HttpClient client;
+            TestHelpers::TempFile tempFile;
+
+            try
+            {
+                auto result = client.download(
+                    winrt::Windows::Foundation::Uri(L"https://invalid.invalid.invalid"),
+                    tempFile.path());
+                // May return false or throw
+            }
+            catch (...)
+            {
+                // Exception is acceptable for invalid/unreachable URI
+            }
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(HttpClient_Download_WithCallback_DoesNotCrash)
+        {
+            http::HttpClient client;
+            TestHelpers::TempFile tempFile;
+            std::atomic<int> callbackCount{ 0 };
+
+            try
+            {
+                auto result = client.download(
+                    winrt::Windows::Foundation::Uri(L"https://invalid.invalid.invalid"),
+                    tempFile.path(),
+                    [&callbackCount]([[maybe_unused]] float progress) {
+                        callbackCount++;
+                    });
+            }
+            catch (...)
+            {
+                // Exception is acceptable
+            }
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(HttpClient_Download_EmptyPath_DoesNotCrash)
+        {
+            http::HttpClient client;
+
+            try
+            {
+                auto result = client.download(
+                    winrt::Windows::Foundation::Uri(L"https://example.com"),
+                    L"");
+            }
+            catch (...)
+            {
+                // Exception is acceptable for empty path
+            }
+            Assert::IsTrue(true);
+        }
+
+        // These tests require network access and may be skipped in offline environments
+        TEST_METHOD(HttpClient_Request_ValidUri_ReturnsResult)
+        {
+            // Skip this test in most CI environments
+            // Only run manually to verify network functionality
+            http::HttpClient client;
+
+            try
+            {
+                // Use a reliable, fast-responding URL
+                auto result = client.request(winrt::Windows::Foundation::Uri(L"https://www.microsoft.com"));
+                // Result may or may not be successful depending on network
+            }
+            catch (...)
+            {
+                // Network errors are acceptable in test environment
+            }
+            Assert::IsTrue(true);
+        }
+
+        // Thread safety test (doesn't require network)
+        TEST_METHOD(HttpClient_MultipleInstances_DoNotCrash)
+        {
+            std::vector<std::unique_ptr<http::HttpClient>> clients;
+
+            for (int i = 0; i < 10; ++i)
+            {
+                clients.push_back(std::make_unique<http::HttpClient>());
+            }
+
+            // All clients should coexist without crashing
+            Assert::AreEqual(static_cast<size_t>(10), clients.size());
+        }
+
+        TEST_METHOD(HttpClient_ConcurrentConstruction_DoesNotCrash)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 5; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    http::HttpClient client;
+                    successCount++;
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(5, successCount.load());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Json.Tests.cpp

@@ -0,0 +1,283 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <json.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+using namespace winrt::Windows::Data::Json;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(JsonTests)
+    {
+    public:
+        // from_file tests
+        TEST_METHOD(FromFile_NonExistentFile_ReturnsNullopt)
+        {
+            auto result = json::from_file(L"C:\\NonExistent\\File\\Path.json");
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(FromFile_ValidJsonFile_ReturnsJsonObject)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+            tempFile.write("{\"key\": \"value\"}");
+
+            auto result = json::from_file(tempFile.path());
+            Assert::IsTrue(result.has_value());
+        }
+
+        TEST_METHOD(FromFile_InvalidJson_ReturnsNullopt)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+            tempFile.write("not valid json {{{");
+
+            auto result = json::from_file(tempFile.path());
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(FromFile_EmptyFile_ReturnsNullopt)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+            // File is empty
+
+            auto result = json::from_file(tempFile.path());
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(FromFile_ValidComplexJson_ParsesCorrectly)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+            tempFile.write("{\"name\": \"test\", \"value\": 42, \"enabled\": true}");
+
+            auto result = json::from_file(tempFile.path());
+            Assert::IsTrue(result.has_value());
+
+            auto& obj = *result;
+            Assert::IsTrue(obj.HasKey(L"name"));
+            Assert::IsTrue(obj.HasKey(L"value"));
+            Assert::IsTrue(obj.HasKey(L"enabled"));
+        }
+
+        // to_file tests
+        TEST_METHOD(ToFile_ValidObject_WritesFile)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+
+            JsonObject obj;
+            obj.SetNamedValue(L"key", JsonValue::CreateStringValue(L"value"));
+            json::to_file(tempFile.path(), obj);
+
+            // Read back and verify
+            auto result = json::from_file(tempFile.path());
+            Assert::IsTrue(result.has_value());
+            Assert::IsTrue(result->HasKey(L"key"));
+        }
+
+        TEST_METHOD(ToFile_ComplexObject_WritesFile)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+
+            JsonObject obj;
+            obj.SetNamedValue(L"name", JsonValue::CreateStringValue(L"test"));
+            obj.SetNamedValue(L"value", JsonValue::CreateNumberValue(42));
+            obj.SetNamedValue(L"enabled", JsonValue::CreateBooleanValue(true));
+            json::to_file(tempFile.path(), obj);
+
+            auto result = json::from_file(tempFile.path());
+            Assert::IsTrue(result.has_value());
+            Assert::AreEqual(std::wstring(L"test"), std::wstring(result->GetNamedString(L"name")));
+            Assert::AreEqual(42.0, result->GetNamedNumber(L"value"));
+            Assert::IsTrue(result->GetNamedBoolean(L"enabled"));
+        }
+
+        // has tests
+        TEST_METHOD(Has_ExistingKey_ReturnsTrue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"key", JsonValue::CreateStringValue(L"value"));
+            Assert::IsTrue(json::has(obj, L"key", JsonValueType::String));
+        }
+
+        TEST_METHOD(Has_NonExistingKey_ReturnsFalse)
+        {
+            JsonObject obj;
+            Assert::IsFalse(json::has(obj, L"key", JsonValueType::String));
+        }
+
+        TEST_METHOD(Has_WrongType_ReturnsFalse)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"key", JsonValue::CreateStringValue(L"value"));
+            Assert::IsFalse(json::has(obj, L"key", JsonValueType::Number));
+        }
+
+        TEST_METHOD(Has_NumberType_ReturnsTrue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"key", JsonValue::CreateNumberValue(42));
+            Assert::IsTrue(json::has(obj, L"key", JsonValueType::Number));
+        }
+
+        TEST_METHOD(Has_BooleanType_ReturnsTrue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"key", JsonValue::CreateBooleanValue(true));
+            Assert::IsTrue(json::has(obj, L"key", JsonValueType::Boolean));
+        }
+
+        TEST_METHOD(Has_ObjectType_ReturnsTrue)
+        {
+            JsonObject obj;
+            JsonObject nested;
+            obj.SetNamedValue(L"key", nested);
+            Assert::IsTrue(json::has(obj, L"key", JsonValueType::Object));
+        }
+
+        // value function tests
+        TEST_METHOD(Value_IntegerType_CreatesNumberValue)
+        {
+            auto val = json::value(42);
+            Assert::IsTrue(val.ValueType() == JsonValueType::Number);
+            Assert::AreEqual(42.0, val.GetNumber());
+        }
+
+        TEST_METHOD(Value_DoubleType_CreatesNumberValue)
+        {
+            auto val = json::value(3.14);
+            Assert::IsTrue(val.ValueType() == JsonValueType::Number);
+            Assert::AreEqual(3.14, val.GetNumber());
+        }
+
+        TEST_METHOD(Value_BooleanTrue_CreatesBooleanValue)
+        {
+            auto val = json::value(true);
+            Assert::IsTrue(val.ValueType() == JsonValueType::Boolean);
+            Assert::IsTrue(val.GetBoolean());
+        }
+
+        TEST_METHOD(Value_BooleanFalse_CreatesBooleanValue)
+        {
+            auto val = json::value(false);
+            Assert::IsTrue(val.ValueType() == JsonValueType::Boolean);
+            Assert::IsFalse(val.GetBoolean());
+        }
+
+        TEST_METHOD(Value_String_CreatesStringValue)
+        {
+            auto val = json::value(L"hello");
+            Assert::IsTrue(val.ValueType() == JsonValueType::String);
+            Assert::AreEqual(std::wstring(L"hello"), std::wstring(val.GetString()));
+        }
+
+        TEST_METHOD(Value_JsonObject_ReturnsJsonValue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"key", JsonValue::CreateStringValue(L"value"));
+            auto val = json::value(obj);
+            Assert::IsTrue(val.ValueType() == JsonValueType::Object);
+        }
+
+        TEST_METHOD(Value_JsonValue_ReturnsIdentity)
+        {
+            auto original = JsonValue::CreateStringValue(L"test");
+            auto result = json::value(original);
+            Assert::AreEqual(std::wstring(L"test"), std::wstring(result.GetString()));
+        }
+
+        // get function tests
+        TEST_METHOD(Get_BooleanValue_ReturnsValue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"enabled", JsonValue::CreateBooleanValue(true));
+
+            bool result = false;
+            json::get(obj, L"enabled", result);
+            Assert::IsTrue(result);
+        }
+
+        TEST_METHOD(Get_IntValue_ReturnsValue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"count", JsonValue::CreateNumberValue(42));
+
+            int result = 0;
+            json::get(obj, L"count", result);
+            Assert::AreEqual(42, result);
+        }
+
+        TEST_METHOD(Get_DoubleValue_ReturnsValue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"ratio", JsonValue::CreateNumberValue(3.14));
+
+            double result = 0.0;
+            json::get(obj, L"ratio", result);
+            Assert::AreEqual(3.14, result);
+        }
+
+        TEST_METHOD(Get_StringValue_ReturnsValue)
+        {
+            JsonObject obj;
+            obj.SetNamedValue(L"name", JsonValue::CreateStringValue(L"test"));
+
+            std::wstring result;
+            json::get(obj, L"name", result);
+            Assert::AreEqual(std::wstring(L"test"), result);
+        }
+
+        TEST_METHOD(Get_MissingKey_UsesDefault)
+        {
+            JsonObject obj;
+
+            int result = 0;
+            json::get(obj, L"missing", result, 99);
+            Assert::AreEqual(99, result);
+        }
+
+        TEST_METHOD(Get_MissingKeyNoDefault_PreservesOriginal)
+        {
+            JsonObject obj;
+
+            int result = 42;
+            json::get(obj, L"missing", result);
+            // When key is missing and no default, original value is preserved
+            Assert::AreEqual(42, result);
+        }
+
+        TEST_METHOD(Get_JsonObject_ReturnsObject)
+        {
+            JsonObject obj;
+            JsonObject nested;
+            nested.SetNamedValue(L"inner", JsonValue::CreateStringValue(L"value"));
+            obj.SetNamedValue(L"nested", nested);
+
+            JsonObject result;
+            json::get(obj, L"nested", result);
+            Assert::IsTrue(result.HasKey(L"inner"));
+        }
+
+        // Roundtrip tests
+        TEST_METHOD(Roundtrip_ComplexObject_PreservesData)
+        {
+            TestHelpers::TempFile tempFile(L"", L".json");
+
+            JsonObject original;
+            original.SetNamedValue(L"string", JsonValue::CreateStringValue(L"hello"));
+            original.SetNamedValue(L"number", JsonValue::CreateNumberValue(42));
+            original.SetNamedValue(L"boolean", JsonValue::CreateBooleanValue(true));
+
+            JsonObject nested;
+            nested.SetNamedValue(L"inner", JsonValue::CreateStringValue(L"world"));
+            original.SetNamedValue(L"object", nested);
+
+            json::to_file(tempFile.path(), original);
+            auto loaded = json::from_file(tempFile.path());
+
+            Assert::IsTrue(loaded.has_value());
+            Assert::AreEqual(std::wstring(L"hello"), std::wstring(loaded->GetNamedString(L"string")));
+            Assert::AreEqual(42.0, loaded->GetNamedNumber(L"number"));
+            Assert::IsTrue(loaded->GetNamedBoolean(L"boolean"));
+            Assert::AreEqual(std::wstring(L"world"), std::wstring(loaded->GetNamedObject(L"object").GetNamedString(L"inner")));
+        }
+    };
+}

src/common/UnitTests-CommonUtils/LoggerHelper.Tests.cpp

@@ -0,0 +1,180 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <logger_helper.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+using namespace LoggerHelpers;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(LoggerHelperTests)
+    {
+    public:
+        // get_log_folder_path tests
+        TEST_METHOD(GetLogFolderPath_ValidAppPath_ReturnsPath)
+        {
+            auto result = get_log_folder_path(L"TestApp");
+
+            Assert::IsFalse(result.empty());
+            // Should contain the app name or be a valid path
+            auto pathStr = result.wstring();
+            Assert::IsTrue(pathStr.length() > 0);
+        }
+
+        TEST_METHOD(GetLogFolderPath_EmptyAppPath_ReturnsPath)
+        {
+            auto result = get_log_folder_path(L"");
+
+            // Should still return a base path
+            Assert::IsTrue(true); // Just verify no crash
+        }
+
+        TEST_METHOD(GetLogFolderPath_SpecialCharacters_Works)
+        {
+            auto result = get_log_folder_path(L"Test App With Spaces");
+
+            // Should handle spaces in path
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetLogFolderPath_ConsistentResults)
+        {
+            auto result1 = get_log_folder_path(L"TestApp");
+            auto result2 = get_log_folder_path(L"TestApp");
+
+            Assert::AreEqual(result1.wstring(), result2.wstring());
+        }
+
+        // dir_exists tests
+        TEST_METHOD(DirExists_WindowsDirectory_ReturnsTrue)
+        {
+            bool result = dir_exists(std::filesystem::path(L"C:\\Windows"));
+            Assert::IsTrue(result);
+        }
+
+        TEST_METHOD(DirExists_NonExistentDirectory_ReturnsFalse)
+        {
+            bool result = dir_exists(std::filesystem::path(L"C:\\NonExistentDir12345"));
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(DirExists_FileInsteadOfDir_ReturnsTrue)
+        {
+            // notepad.exe is a file, not a directory
+            bool result = dir_exists(std::filesystem::path(L"C:\\Windows\\notepad.exe"));
+            Assert::IsTrue(result);
+        }
+
+        TEST_METHOD(DirExists_EmptyPath_ReturnsFalse)
+        {
+            bool result = dir_exists(std::filesystem::path(L""));
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(DirExists_TempDirectory_ReturnsTrue)
+        {
+            wchar_t tempPath[MAX_PATH];
+            GetTempPathW(MAX_PATH, tempPath);
+
+            bool result = dir_exists(std::filesystem::path(tempPath));
+            Assert::IsTrue(result);
+        }
+
+        // delete_old_log_folder tests
+        TEST_METHOD(DeleteOldLogFolder_NonExistentFolder_DoesNotCrash)
+        {
+            delete_old_log_folder(std::filesystem::path(L"C:\\NonExistentLogFolder12345"));
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(DeleteOldLogFolder_ValidEmptyFolder_Works)
+        {
+            TestHelpers::TempDirectory tempDir;
+
+            // Create a subfolder structure
+            auto logFolder = std::filesystem::path(tempDir.path()) / L"logs";
+            std::filesystem::create_directories(logFolder);
+
+            Assert::IsTrue(std::filesystem::exists(logFolder));
+
+            delete_old_log_folder(logFolder);
+
+            // Folder may or may not be deleted depending on implementation
+            Assert::IsTrue(true);
+        }
+
+        // delete_other_versions_log_folders tests
+        TEST_METHOD(DeleteOtherVersionsLogFolders_NonExistentPath_DoesNotCrash)
+        {
+            delete_other_versions_log_folders(L"C:\\NonExistent\\Path", L"1.0.0");
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(DeleteOtherVersionsLogFolders_EmptyVersion_DoesNotCrash)
+        {
+            wchar_t tempPath[MAX_PATH];
+            GetTempPathW(MAX_PATH, tempPath);
+
+            delete_other_versions_log_folders(tempPath, L"");
+            Assert::IsTrue(true);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(GetLogFolderPath_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount, i]() {
+                    auto path = get_log_folder_path(L"TestApp" + std::to_wstring(i));
+                    if (!path.empty())
+                    {
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(10, successCount.load());
+        }
+
+        TEST_METHOD(DirExists_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        dir_exists(std::filesystem::path(L"C:\\Windows"));
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+
+        // Path construction tests
+        TEST_METHOD(GetLogFolderPath_ReturnsValidFilesystemPath)
+        {
+            auto result = get_log_folder_path(L"TestApp");
+
+            // Should be a valid path that we can use with filesystem operations
+            Assert::IsTrue(result.is_absolute() || result.has_root_name() || !result.empty());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ModulesRegistry.Tests.cpp

@@ -0,0 +1,173 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <modulesRegistry.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    static std::wstring GetInstallDir()
+    {
+        wchar_t path[MAX_PATH];
+        GetModuleFileNameW(nullptr, path, MAX_PATH);
+        return std::filesystem::path{ path }.parent_path().wstring();
+    }
+
+    TEST_CLASS(ModulesRegistryTests)
+    {
+    public:
+        // Test that all changeset generator functions return valid changesets
+        TEST_METHOD(GetSvgPreviewHandlerChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getSvgPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetSvgThumbnailProviderChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getSvgThumbnailHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetMarkdownPreviewHandlerChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getMdPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetMonacoPreviewHandlerChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getMonacoPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetPdfPreviewHandlerChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getPdfPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetPdfThumbnailProviderChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getPdfThumbnailHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetGcodePreviewHandlerChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getGcodePreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetGcodeThumbnailProviderChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getGcodeThumbnailHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetStlThumbnailProviderChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getStlThumbnailHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetQoiPreviewHandlerChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getQoiPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        TEST_METHOD(GetQoiThumbnailProviderChangeSet_ReturnsChangeSet)
+        {
+            auto changeSet = getQoiThumbnailHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        // Test enabled vs disabled state
+        TEST_METHOD(ChangeSet_EnabledVsDisabled_MayDiffer)
+        {
+            auto enabledSet = getSvgPreviewHandlerChangeSet(GetInstallDir(), true);
+            auto disabledSet = getSvgPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            // Both should be valid change sets
+            Assert::IsFalse(enabledSet.changes.empty());
+            Assert::IsFalse(disabledSet.changes.empty());
+        }
+
+        // Test getAllOnByDefaultModulesChangeSets
+        TEST_METHOD(GetAllOnByDefaultModulesChangeSets_ReturnsMultipleChangeSets)
+        {
+            auto changeSets = getAllOnByDefaultModulesChangeSets(GetInstallDir());
+
+            // Should return multiple changesets for all default-enabled modules
+            Assert::IsTrue(changeSets.size() > 0);
+        }
+
+        // Test getAllModulesChangeSets
+        TEST_METHOD(GetAllModulesChangeSets_ReturnsChangeSets)
+        {
+            auto changeSets = getAllModulesChangeSets(GetInstallDir());
+
+            // Should return changesets for all modules
+            Assert::IsTrue(changeSets.size() > 0);
+        }
+
+        TEST_METHOD(GetAllModulesChangeSets_ContainsMoreThanOnByDefault)
+        {
+            auto allSets = getAllModulesChangeSets(GetInstallDir());
+            auto defaultSets = getAllOnByDefaultModulesChangeSets(GetInstallDir());
+
+            // All modules should be >= on-by-default modules
+            Assert::IsTrue(allSets.size() >= defaultSets.size());
+        }
+
+        // Test that changesets have valid structure
+        TEST_METHOD(ChangeSet_HasValidKeyPath)
+        {
+            auto changeSet = getSvgPreviewHandlerChangeSet(GetInstallDir(), false);
+
+            Assert::IsFalse(changeSet.changes.empty());
+        }
+
+        // Test all changeset functions don't crash
+        TEST_METHOD(AllChangeSetFunctions_DoNotCrash)
+        {
+            auto installDir = GetInstallDir();
+            getSvgPreviewHandlerChangeSet(installDir, true);
+            getSvgPreviewHandlerChangeSet(installDir, false);
+            getSvgThumbnailHandlerChangeSet(installDir, true);
+            getSvgThumbnailHandlerChangeSet(installDir, false);
+            getMdPreviewHandlerChangeSet(installDir, true);
+            getMdPreviewHandlerChangeSet(installDir, false);
+            getMonacoPreviewHandlerChangeSet(installDir, true);
+            getMonacoPreviewHandlerChangeSet(installDir, false);
+            getPdfPreviewHandlerChangeSet(installDir, true);
+            getPdfPreviewHandlerChangeSet(installDir, false);
+            getPdfThumbnailHandlerChangeSet(installDir, true);
+            getPdfThumbnailHandlerChangeSet(installDir, false);
+            getGcodePreviewHandlerChangeSet(installDir, true);
+            getGcodePreviewHandlerChangeSet(installDir, false);
+            getGcodeThumbnailHandlerChangeSet(installDir, true);
+            getGcodeThumbnailHandlerChangeSet(installDir, false);
+            getStlThumbnailHandlerChangeSet(installDir, true);
+            getStlThumbnailHandlerChangeSet(installDir, false);
+            getQoiPreviewHandlerChangeSet(installDir, true);
+            getQoiPreviewHandlerChangeSet(installDir, false);
+            getQoiThumbnailHandlerChangeSet(installDir, true);
+            getQoiThumbnailHandlerChangeSet(installDir, false);
+
+            Assert::IsTrue(true);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/MsWindowsSettings.Tests.cpp

@@ -0,0 +1,65 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <MsWindowsSettings.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(MsWindowsSettingsTests)
+    {
+    public:
+        TEST_METHOD(GetAnimationsEnabled_ReturnsBoolean)
+        {
+            bool result = GetAnimationsEnabled();
+
+            // Should return a valid boolean
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(GetAnimationsEnabled_ConsistentResults)
+        {
+            // Multiple calls should return consistent results
+            bool result1 = GetAnimationsEnabled();
+            bool result2 = GetAnimationsEnabled();
+            bool result3 = GetAnimationsEnabled();
+
+            Assert::AreEqual(result1, result2);
+            Assert::AreEqual(result2, result3);
+        }
+
+        TEST_METHOD(GetAnimationsEnabled_DoesNotCrash)
+        {
+            // Call multiple times to ensure stability
+            for (int i = 0; i < 100; ++i)
+            {
+                GetAnimationsEnabled();
+            }
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetAnimationsEnabled_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        GetAnimationsEnabled();
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/MsiUtils.Tests.cpp

@@ -0,0 +1,146 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <MsiUtils.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(MsiUtilsTests)
+    {
+    public:
+        // GetMsiPackageInstalledPath tests
+        TEST_METHOD(GetMsiPackageInstalledPath_PerUser_DoesNotCrash)
+        {
+            auto result = GetMsiPackageInstalledPath(true);
+            // Result depends on installation state, but should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetMsiPackageInstalledPath_PerMachine_DoesNotCrash)
+        {
+            auto result = GetMsiPackageInstalledPath(false);
+            // Result depends on installation state, but should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetMsiPackageInstalledPath_ConsistentResults)
+        {
+            auto result1 = GetMsiPackageInstalledPath(true);
+            auto result2 = GetMsiPackageInstalledPath(true);
+
+            // Results should be consistent
+            Assert::AreEqual(result1.has_value(), result2.has_value());
+            if (result1.has_value() && result2.has_value())
+            {
+                Assert::AreEqual(*result1, *result2);
+            }
+        }
+
+        TEST_METHOD(GetMsiPackageInstalledPath_PerUserVsPerMachine_MayDiffer)
+        {
+            auto perUser = GetMsiPackageInstalledPath(true);
+            auto perMachine = GetMsiPackageInstalledPath(false);
+
+            // These may or may not be equal depending on installation
+            // Just verify they don't crash
+            Assert::IsTrue(true);
+        }
+
+        // GetMsiPackagePath tests
+        TEST_METHOD(GetMsiPackagePath_DoesNotCrash)
+        {
+            auto result = GetMsiPackagePath();
+            // Result depends on installation state, but should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetMsiPackagePath_ConsistentResults)
+        {
+            auto result1 = GetMsiPackagePath();
+            auto result2 = GetMsiPackagePath();
+
+            // Results should be consistent
+            Assert::AreEqual(result1, result2);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(GetMsiPackageInstalledPath_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 5; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 5; ++j)
+                    {
+                        GetMsiPackageInstalledPath(j % 2 == 0);
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(25, successCount.load());
+        }
+
+        TEST_METHOD(GetMsiPackagePath_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 5; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 5; ++j)
+                    {
+                        GetMsiPackagePath();
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(25, successCount.load());
+        }
+
+        // Return value format tests
+        TEST_METHOD(GetMsiPackageInstalledPath_ReturnsValidPathOrEmpty)
+        {
+            auto path = GetMsiPackageInstalledPath(true);
+
+            if (path.has_value() && !path->empty())
+            {
+                // If a path is returned, it should contain backslash or be a valid path format
+                Assert::IsTrue(path->find(L'\\') != std::wstring::npos ||
+                              path->find(L'/') != std::wstring::npos ||
+                              path->length() >= 2); // At minimum drive letter + colon
+            }
+            // No value or empty is also valid (not installed)
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetMsiPackagePath_ReturnsValidPathOrEmpty)
+        {
+            auto path = GetMsiPackagePath();
+
+            if (!path.empty())
+            {
+                // If a path is returned, it should be a valid path format
+                Assert::IsTrue(path.find(L'\\') != std::wstring::npos ||
+                              path.find(L'/') != std::wstring::npos ||
+                              path.length() >= 2);
+            }
+            Assert::IsTrue(true);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/OsDetect.Tests.cpp

@@ -0,0 +1,107 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <os-detect.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(OsDetectTests)
+    {
+    public:
+        // IsAPIContractVxAvailable tests
+        TEST_METHOD(IsAPIContractV8Available_ReturnsBoolean)
+        {
+            // This test verifies the function runs without crashing
+            // The actual result depends on the OS version
+            bool result = IsAPIContractV8Available();
+            // Result is either true or false, both are valid
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsAPIContractVxAvailable_V1_ReturnsTrue)
+        {
+            // API contract v1 should be available on any modern Windows
+            bool result = IsAPIContractVxAvailable<1>();
+            Assert::IsTrue(result);
+        }
+
+        TEST_METHOD(IsAPIContractVxAvailable_V5_ReturnsBooleanConsistently)
+        {
+            // Call multiple times to verify caching works correctly
+            bool result1 = IsAPIContractVxAvailable<5>();
+            bool result2 = IsAPIContractVxAvailable<5>();
+            bool result3 = IsAPIContractVxAvailable<5>();
+            Assert::AreEqual(result1, result2);
+            Assert::AreEqual(result2, result3);
+        }
+
+        TEST_METHOD(IsAPIContractVxAvailable_V10_ReturnsBoolean)
+        {
+            bool result = IsAPIContractVxAvailable<10>();
+            // Result depends on Windows version, but should not crash
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsAPIContractVxAvailable_V15_ReturnsBoolean)
+        {
+            bool result = IsAPIContractVxAvailable<15>();
+            // Higher API versions, may or may not be available
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        // Is19H1OrHigher tests
+        TEST_METHOD(Is19H1OrHigher_ReturnsBoolean)
+        {
+            bool result = Is19H1OrHigher();
+            // Result depends on OS version, but should not crash
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(Is19H1OrHigher_ReturnsSameAsV8Contract)
+        {
+            // Is19H1OrHigher is implemented as IsAPIContractV8Available
+            bool is19H1 = Is19H1OrHigher();
+            bool isV8 = IsAPIContractV8Available();
+            Assert::AreEqual(is19H1, isV8);
+        }
+
+        TEST_METHOD(Is19H1OrHigher_ConsistentAcrossMultipleCalls)
+        {
+            bool result1 = Is19H1OrHigher();
+            bool result2 = Is19H1OrHigher();
+            bool result3 = Is19H1OrHigher();
+            Assert::AreEqual(result1, result2);
+            Assert::AreEqual(result2, result3);
+        }
+
+        // Static caching behavior tests
+        TEST_METHOD(StaticCaching_DifferentContractVersions_IndependentResults)
+        {
+            // Each template instantiation has its own static variable
+            bool v1 = IsAPIContractVxAvailable<1>();
+            (void)v1; // Suppress unused variable warning
+
+            // v1 should be true on any modern Windows
+            Assert::IsTrue(v1);
+        }
+
+        // Performance test (optional - verifies caching)
+        TEST_METHOD(Performance_MultipleCallsAreFast)
+        {
+            // The static caching should make subsequent calls very fast
+            auto start = std::chrono::high_resolution_clock::now();
+
+            for (int i = 0; i < 10000; ++i)
+            {
+                Is19H1OrHigher();
+            }
+
+            auto end = std::chrono::high_resolution_clock::now();
+            auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
+
+            // 10000 calls should complete in well under 1 second due to caching
+            Assert::IsTrue(duration.count() < 1000);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Package.Tests.cpp

@@ -0,0 +1,180 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <package.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+using namespace package;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(PackageTests)
+    {
+    public:
+        // IsWin11OrGreater tests
+        TEST_METHOD(IsWin11OrGreater_ReturnsBoolean)
+        {
+            bool result = IsWin11OrGreater();
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsWin11OrGreater_ConsistentResults)
+        {
+            bool result1 = IsWin11OrGreater();
+            bool result2 = IsWin11OrGreater();
+            bool result3 = IsWin11OrGreater();
+
+            Assert::AreEqual(result1, result2);
+            Assert::AreEqual(result2, result3);
+        }
+
+        // PACKAGE_VERSION struct tests
+        TEST_METHOD(PackageVersion_DefaultConstruction)
+        {
+            PACKAGE_VERSION version{};
+            Assert::AreEqual(static_cast<UINT16>(0), version.Major);
+            Assert::AreEqual(static_cast<UINT16>(0), version.Minor);
+            Assert::AreEqual(static_cast<UINT16>(0), version.Build);
+            Assert::AreEqual(static_cast<UINT16>(0), version.Revision);
+        }
+
+        TEST_METHOD(PackageVersion_Assignment)
+        {
+            PACKAGE_VERSION version{};
+            version.Major = 1;
+            version.Minor = 2;
+            version.Build = 3;
+            version.Revision = 4;
+
+            Assert::AreEqual(static_cast<UINT16>(1), version.Major);
+            Assert::AreEqual(static_cast<UINT16>(2), version.Minor);
+            Assert::AreEqual(static_cast<UINT16>(3), version.Build);
+            Assert::AreEqual(static_cast<UINT16>(4), version.Revision);
+        }
+
+        // ComInitializer tests
+        TEST_METHOD(ComInitializer_InitializesAndUninitializesCom)
+        {
+            {
+                ComInitializer comInit;
+                // COM should be initialized within this scope
+            }
+            // COM should be uninitialized after scope
+
+            // Verify we can initialize again
+            {
+                ComInitializer comInit2;
+            }
+
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(ComInitializer_MultipleInstances)
+        {
+            ComInitializer init1;
+            ComInitializer init2;
+            ComInitializer init3;
+
+            // Multiple initializations should work (COM uses reference counting)
+            Assert::IsTrue(true);
+        }
+
+        // GetRegisteredPackage tests
+        TEST_METHOD(GetRegisteredPackage_NonExistentPackage_ReturnsEmpty)
+        {
+            auto result = GetRegisteredPackage(L"NonExistentPackage12345", false);
+
+            // Should return empty for non-existent package
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(GetRegisteredPackage_EmptyName_DoesNotCrash)
+        {
+            auto result = GetRegisteredPackage(L"", false);
+            // Behavior may vary based on package enumeration; just ensure it doesn't crash.
+            Assert::IsTrue(true);
+        }
+
+        // IsPackageRegisteredWithPowerToysVersion tests
+        TEST_METHOD(IsPackageRegisteredWithPowerToysVersion_NonExistentPackage_ReturnsFalse)
+        {
+            bool result = IsPackageRegisteredWithPowerToysVersion(L"NonExistentPackage12345");
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(IsPackageRegisteredWithPowerToysVersion_EmptyName_ReturnsFalse)
+        {
+            bool result = IsPackageRegisteredWithPowerToysVersion(L"");
+            Assert::IsFalse(result);
+        }
+
+        // FindMsixFile tests
+        TEST_METHOD(FindMsixFile_NonExistentDirectory_ReturnsEmpty)
+        {
+            auto result = FindMsixFile(L"C:\\NonExistentDirectory12345", false);
+            Assert::IsTrue(result.empty());
+        }
+
+        TEST_METHOD(FindMsixFile_SystemDirectory_DoesNotCrash)
+        {
+            // System32 probably doesn't have MSIX files, but shouldn't crash
+            auto result = FindMsixFile(L"C:\\Windows\\System32", false);
+            // May or may not find files, but should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(FindMsixFile_RecursiveSearch_DoesNotCrash)
+        {
+            // Use temp directory which should exist
+            wchar_t tempPath[MAX_PATH];
+            GetTempPathW(MAX_PATH, tempPath);
+
+            auto result = FindMsixFile(tempPath, true);
+            // May or may not find files, but should not crash
+            Assert::IsTrue(true);
+        }
+
+        // GetPackageNameAndVersionFromAppx tests
+        TEST_METHOD(GetPackageNameAndVersionFromAppx_NonExistentFile_ReturnsFalse)
+        {
+            std::wstring name;
+            PACKAGE_VERSION version{};
+
+            bool result = GetPackageNameAndVersionFromAppx(L"C:\\NonExistent\\file.msix", name, version);
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(GetPackageNameAndVersionFromAppx_EmptyPath_ReturnsFalse)
+        {
+            std::wstring name;
+            PACKAGE_VERSION version{};
+
+            bool result = GetPackageNameAndVersionFromAppx(L"", name, version);
+            Assert::IsFalse(result);
+        }
+
+        // Thread safety
+        TEST_METHOD(IsWin11OrGreater_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        IsWin11OrGreater();
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ProcessApi.Tests.cpp

@@ -0,0 +1,136 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <processApi.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ProcessApiTests)
+    {
+    public:
+        TEST_METHOD(GetProcessHandlesByName_CurrentProcess_ReturnsHandles)
+        {
+            // Get current process executable name
+            wchar_t path[MAX_PATH];
+            GetModuleFileNameW(nullptr, path, MAX_PATH);
+
+            // Extract just the filename
+            std::wstring fullPath(path);
+            auto lastSlash = fullPath.rfind(L'\\');
+            std::wstring exeName = (lastSlash != std::wstring::npos) ?
+                fullPath.substr(lastSlash + 1) : fullPath;
+
+            auto handles = getProcessHandlesByName(exeName, PROCESS_QUERY_LIMITED_INFORMATION);
+
+            // Should find at least our own process
+            Assert::IsFalse(handles.empty());
+
+            // Handles are RAII-managed
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_NonExistentProcess_ReturnsEmpty)
+        {
+            auto handles = getProcessHandlesByName(L"NonExistentProcess12345.exe", PROCESS_QUERY_LIMITED_INFORMATION);
+            Assert::IsTrue(handles.empty());
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_EmptyName_ReturnsEmpty)
+        {
+            auto handles = getProcessHandlesByName(L"", PROCESS_QUERY_LIMITED_INFORMATION);
+            Assert::IsTrue(handles.empty());
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_Explorer_ReturnsHandles)
+        {
+            // Explorer.exe should typically be running
+            auto handles = getProcessHandlesByName(L"explorer.exe", PROCESS_QUERY_LIMITED_INFORMATION);
+
+            // Handles are RAII-managed
+
+            // May or may not find explorer depending on system state
+            // Just verify it doesn't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_CaseInsensitive_Works)
+        {
+            // Get current process name in uppercase
+            wchar_t path[MAX_PATH];
+            GetModuleFileNameW(nullptr, path, MAX_PATH);
+
+            std::wstring fullPath(path);
+            auto lastSlash = fullPath.rfind(L'\\');
+            std::wstring exeName = (lastSlash != std::wstring::npos) ?
+                fullPath.substr(lastSlash + 1) : fullPath;
+
+            // Convert to uppercase
+            std::wstring upperName = exeName;
+            std::transform(upperName.begin(), upperName.end(), upperName.begin(), ::towupper);
+
+            auto handles = getProcessHandlesByName(upperName, PROCESS_QUERY_LIMITED_INFORMATION);
+
+            // Handles are RAII-managed
+
+            // The function may or may not be case insensitive - just don't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_DifferentAccessRights_Works)
+        {
+            wchar_t path[MAX_PATH];
+            GetModuleFileNameW(nullptr, path, MAX_PATH);
+
+            std::wstring fullPath(path);
+            auto lastSlash = fullPath.rfind(L'\\');
+            std::wstring exeName = (lastSlash != std::wstring::npos) ?
+                fullPath.substr(lastSlash + 1) : fullPath;
+
+            // Try with different access rights
+            auto handles1 = getProcessHandlesByName(exeName, PROCESS_QUERY_INFORMATION);
+            auto handles2 = getProcessHandlesByName(exeName, PROCESS_VM_READ);
+
+            // Handles are RAII-managed
+
+            // Just verify no crashes
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_SystemProcess_MayRequireElevation)
+        {
+            // System processes might require elevation
+            auto handles = getProcessHandlesByName(L"System", PROCESS_QUERY_LIMITED_INFORMATION);
+
+            // Handles are RAII-managed
+
+            // Just verify no crashes
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetProcessHandlesByName_ValidHandles_AreUsable)
+        {
+            wchar_t path[MAX_PATH];
+            GetModuleFileNameW(nullptr, path, MAX_PATH);
+
+            std::wstring fullPath(path);
+            auto lastSlash = fullPath.rfind(L'\\');
+            std::wstring exeName = (lastSlash != std::wstring::npos) ?
+                fullPath.substr(lastSlash + 1) : fullPath;
+
+            auto handles = getProcessHandlesByName(exeName, PROCESS_QUERY_LIMITED_INFORMATION);
+
+            bool foundValidHandle = false;
+            for (auto& handle : handles)
+            {
+                // Try to use the handle
+                DWORD exitCode;
+                if (GetExitCodeProcess(handle.get(), &exitCode))
+                {
+                    foundValidHandle = true;
+                }
+            }
+
+            Assert::IsTrue(foundValidHandle || handles.empty());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ProcessPath.Tests.cpp

@@ -0,0 +1,153 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <process_path.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ProcessPathTests)
+    {
+    public:
+        // get_process_path (by PID) tests
+        TEST_METHOD(GetProcessPath_CurrentProcess_ReturnsPath)
+        {
+            DWORD pid = GetCurrentProcessId();
+            auto path = get_process_path(pid);
+
+            Assert::IsFalse(path.empty());
+            Assert::IsTrue(path.find(L".exe") != std::wstring::npos ||
+                          path.find(L".dll") != std::wstring::npos);
+        }
+
+        TEST_METHOD(GetProcessPath_InvalidPid_ReturnsEmpty)
+        {
+            DWORD invalidPid = 0xFFFFFFFF;
+            auto path = get_process_path(invalidPid);
+
+            // Should return empty for invalid PID
+            Assert::IsTrue(path.empty());
+        }
+
+        TEST_METHOD(GetProcessPath_ZeroPid_ReturnsEmpty)
+        {
+            auto path = get_process_path(static_cast<DWORD>(0));
+            // PID 0 is the System Idle Process, might return empty or a path
+            // Just verify it doesn't crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetProcessPath_SystemPid_DoesNotCrash)
+        {
+            // PID 4 is typically the System process
+            auto path = get_process_path(static_cast<DWORD>(4));
+            // May return empty due to access rights, but shouldn't crash
+            Assert::IsTrue(true);
+        }
+
+        // get_module_filename tests
+        TEST_METHOD(GetModuleFilename_NullModule_ReturnsExePath)
+        {
+            auto path = get_module_filename(nullptr);
+
+            Assert::IsFalse(path.empty());
+            Assert::IsTrue(path.find(L".exe") != std::wstring::npos ||
+                          path.find(L".dll") != std::wstring::npos);
+        }
+
+        TEST_METHOD(GetModuleFilename_Kernel32_ReturnsPath)
+        {
+            HMODULE kernel32 = GetModuleHandleW(L"kernel32.dll");
+            Assert::IsNotNull(kernel32);
+
+            auto path = get_module_filename(kernel32);
+
+            Assert::IsFalse(path.empty());
+            // Should contain kernel32 (case insensitive check)
+            std::wstring lowerPath = path;
+            std::transform(lowerPath.begin(), lowerPath.end(), lowerPath.begin(), ::towlower);
+            Assert::IsTrue(lowerPath.find(L"kernel32") != std::wstring::npos);
+        }
+
+        TEST_METHOD(GetModuleFilename_InvalidModule_ReturnsEmpty)
+        {
+            auto path = get_module_filename(reinterpret_cast<HMODULE>(0x12345678));
+            // Invalid module should return empty
+            Assert::IsTrue(path.empty());
+        }
+
+        // get_module_folderpath tests
+        TEST_METHOD(GetModuleFolderpath_NullModule_ReturnsFolder)
+        {
+            auto folder = get_module_folderpath(nullptr, true);
+
+            Assert::IsFalse(folder.empty());
+            // Should not end with .exe when removeFilename is true
+            Assert::IsTrue(folder.find(L".exe") == std::wstring::npos);
+            // Should end with backslash or be a valid folder path
+            Assert::IsTrue(folder.back() == L'\\' || folder.find(L"\\") != std::wstring::npos);
+        }
+
+        TEST_METHOD(GetModuleFolderpath_KeepFilename_ReturnsFullPath)
+        {
+            auto fullPath = get_module_folderpath(nullptr, false);
+
+            Assert::IsFalse(fullPath.empty());
+            // Should contain .exe or .dll when not removing filename
+            Assert::IsTrue(fullPath.find(L".exe") != std::wstring::npos ||
+                          fullPath.find(L".dll") != std::wstring::npos);
+        }
+
+        TEST_METHOD(GetModuleFolderpath_Kernel32_ReturnsSystem32)
+        {
+            HMODULE kernel32 = GetModuleHandleW(L"kernel32.dll");
+            Assert::IsNotNull(kernel32);
+
+            auto folder = get_module_folderpath(kernel32, true);
+
+            Assert::IsFalse(folder.empty());
+            // Should be in system32 folder
+            std::wstring lowerPath = folder;
+            std::transform(lowerPath.begin(), lowerPath.end(), lowerPath.begin(), ::towlower);
+            Assert::IsTrue(lowerPath.find(L"system32") != std::wstring::npos ||
+                          lowerPath.find(L"syswow64") != std::wstring::npos);
+        }
+
+        // get_process_path (by HWND) tests
+        TEST_METHOD(GetProcessPath_DesktopWindow_ReturnsPath)
+        {
+            HWND desktop = GetDesktopWindow();
+            Assert::IsNotNull(desktop);
+
+            auto path = get_process_path(desktop);
+            // Desktop window should return a path
+            // (could be explorer.exe or empty depending on system)
+            Assert::IsTrue(true); // Just verify it doesn't crash
+        }
+
+        TEST_METHOD(GetProcessPath_InvalidHwnd_ReturnsEmpty)
+        {
+            auto path = get_process_path(reinterpret_cast<HWND>(0x12345678));
+            Assert::IsTrue(path.empty());
+        }
+
+        TEST_METHOD(GetProcessPath_NullHwnd_ReturnsEmpty)
+        {
+            auto path = get_process_path(static_cast<HWND>(nullptr));
+            Assert::IsTrue(path.empty());
+        }
+
+        // Consistency tests
+        TEST_METHOD(Consistency_ModuleFilenameAndFolderpath_AreRelated)
+        {
+            auto fullPath = get_module_filename(nullptr);
+            auto folder = get_module_folderpath(nullptr, true);
+
+            Assert::IsFalse(fullPath.empty());
+            Assert::IsFalse(folder.empty());
+
+            // Full path should start with the folder
+            Assert::IsTrue(fullPath.find(folder) == 0 || folder.find(fullPath.substr(0, folder.length())) == 0);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/ProcessWaiter.Tests.cpp

@@ -0,0 +1,127 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <ProcessWaiter.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+using namespace ProcessWaiter;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ProcessWaiterTests)
+    {
+    public:
+        TEST_METHOD(OnProcessTerminate_InvalidPid_DoesNotCrash)
+        {
+            std::atomic<bool> called{ false };
+
+            // Use a very unlikely PID (negative value as string will fail conversion)
+            OnProcessTerminate(L"invalid", [&called](DWORD) {
+                called = true;
+            });
+
+            // Wait briefly
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+            // Should not crash, callback may or may not be called depending on implementation
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(OnProcessTerminate_NonExistentPid_DoesNotCrash)
+        {
+            std::atomic<bool> called{ false };
+
+            // Use a PID that likely doesn't exist
+            OnProcessTerminate(L"999999999", [&called](DWORD) {
+                called = true;
+            });
+
+            // Wait briefly
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+            // Should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(OnProcessTerminate_ZeroPid_DoesNotCrash)
+        {
+            std::atomic<bool> called{ false };
+
+            OnProcessTerminate(L"0", [&called](DWORD) {
+                called = true;
+            });
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(OnProcessTerminate_CurrentProcessPid_DoesNotTerminate)
+        {
+            std::atomic<bool> called{ false };
+
+            // Use current process PID - it shouldn't terminate during test
+            std::wstring pid = std::to_wstring(GetCurrentProcessId());
+
+            OnProcessTerminate(pid, [&called](DWORD) {
+                called = true;
+            });
+
+            // Wait briefly - current process should not terminate
+            std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+            // Callback should not have been called since process is still running
+            Assert::IsFalse(called);
+        }
+
+        TEST_METHOD(OnProcessTerminate_EmptyCallback_DoesNotCrash)
+        {
+            // Test with an empty function
+            OnProcessTerminate(L"999999999", std::function<void(DWORD)>());
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(OnProcessTerminate_MultipleCallsForSamePid_DoesNotCrash)
+        {
+            std::atomic<int> counter{ 0 };
+            std::wstring pid = std::to_wstring(GetCurrentProcessId());
+
+            // Multiple waits on same (running) process
+            for (int i = 0; i < 5; ++i)
+            {
+                OnProcessTerminate(pid, [&counter](DWORD) {
+                    counter++;
+                });
+            }
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+            // None should have been called since process is running
+            Assert::AreEqual(0, counter.load());
+        }
+
+        TEST_METHOD(OnProcessTerminate_NegativeNumberString_DoesNotCrash)
+        {
+            std::atomic<bool> called{ false };
+
+            OnProcessTerminate(L"-1", [&called](DWORD) {
+                called = true;
+            });
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(OnProcessTerminate_LargeNumber_DoesNotCrash)
+        {
+            std::atomic<bool> called{ false };
+
+            OnProcessTerminate(L"18446744073709551615", [&called](DWORD) {
+                called = true;
+            });
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            Assert::IsTrue(true);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Registry.Tests.cpp

@@ -0,0 +1,61 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <registry.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(RegistryTests)
+    {
+    public:
+        // Note: These tests use HKCU which doesn't require elevation
+
+        TEST_METHOD(InstallScope_Registry_CanReadAndWrite)
+        {
+            TestHelpers::TestRegistryKey testKey(L"RegistryTest");
+            Assert::IsTrue(testKey.isValid());
+
+            // Write a test value
+            Assert::IsTrue(testKey.setStringValue(L"TestValue", L"TestData"));
+            Assert::IsTrue(testKey.setDwordValue(L"TestDword", 42));
+        }
+
+        TEST_METHOD(Registry_ValueChange_StringValue)
+        {
+            registry::ValueChange change{ HKEY_CURRENT_USER, L"Software\\PowerToys\\Test", L"TestValue", std::wstring{ L"TestData" } };
+
+            Assert::AreEqual(std::wstring(L"Software\\PowerToys\\Test"), change.path);
+            Assert::IsTrue(change.name.has_value());
+            Assert::AreEqual(std::wstring(L"TestValue"), *change.name);
+            Assert::AreEqual(std::wstring(L"TestData"), std::get<std::wstring>(change.value));
+        }
+
+        TEST_METHOD(Registry_ValueChange_DwordValue)
+        {
+            registry::ValueChange change{ HKEY_CURRENT_USER, L"Software\\PowerToys\\Test", L"TestDword", static_cast<DWORD>(42) };
+
+            Assert::AreEqual(std::wstring(L"Software\\PowerToys\\Test"), change.path);
+            Assert::IsTrue(change.name.has_value());
+            Assert::AreEqual(std::wstring(L"TestDword"), *change.name);
+            Assert::AreEqual(static_cast<DWORD>(42), std::get<DWORD>(change.value));
+        }
+
+        TEST_METHOD(Registry_ChangeSet_AddChanges)
+        {
+            registry::ChangeSet changeSet;
+
+            changeSet.changes.push_back({ HKEY_CURRENT_USER, L"Software\\PowerToys\\Test", L"Value1", std::wstring{ L"Data1" } });
+            changeSet.changes.push_back({ HKEY_CURRENT_USER, L"Software\\PowerToys\\Test", L"Value2", static_cast<DWORD>(123) });
+
+            Assert::AreEqual(static_cast<size_t>(2), changeSet.changes.size());
+        }
+
+        TEST_METHOD(InstallScope_GetCurrentInstallScope_ReturnsValidValue)
+        {
+            auto scope = registry::install_scope::get_current_install_scope();
+            Assert::IsTrue(scope == registry::install_scope::InstallScope::PerMachine ||
+                          scope == registry::install_scope::InstallScope::PerUser);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Resources.Tests.cpp

@@ -0,0 +1,144 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <resources.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(ResourcesTests)
+    {
+    public:
+        // get_resource_string tests with current module
+        TEST_METHOD(GetResourceString_NonExistentId_ReturnsFallback)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+
+            auto result = get_resource_string(99999, instance, L"fallback");
+            Assert::AreEqual(std::wstring(L"fallback"), result);
+        }
+
+        TEST_METHOD(GetResourceString_NullInstance_UsesFallback)
+        {
+            auto result = get_resource_string(99999, nullptr, L"fallback");
+            // Should return fallback or empty string
+            Assert::IsTrue(result == L"fallback" || result.empty());
+        }
+
+        TEST_METHOD(GetResourceString_EmptyFallback_ReturnsEmpty)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+
+            auto result = get_resource_string(99999, instance, L"");
+            Assert::IsTrue(result.empty());
+        }
+
+        // get_english_fallback_string tests
+        TEST_METHOD(GetEnglishFallbackString_NonExistentId_ReturnsEmpty)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+
+            auto result = get_english_fallback_string(99999, instance);
+            // Should return empty or the resource if it exists
+            Assert::IsTrue(true); // Just verify no crash
+        }
+
+        TEST_METHOD(GetEnglishFallbackString_NullInstance_DoesNotCrash)
+        {
+            auto result = get_english_fallback_string(99999, nullptr);
+            Assert::IsTrue(true); // Just verify no crash
+        }
+
+        // get_resource_string_language_override tests
+        TEST_METHOD(GetResourceStringLanguageOverride_NonExistentId_ReturnsEmpty)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+
+            auto result = get_resource_string_language_override(99999, instance);
+            // Should return empty for non-existent resource
+            Assert::IsTrue(result.empty() || !result.empty()); // Valid either way
+        }
+
+        TEST_METHOD(GetResourceStringLanguageOverride_NullInstance_DoesNotCrash)
+        {
+            auto result = get_resource_string_language_override(99999, nullptr);
+            Assert::IsTrue(true);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(GetResourceString_ThreadSafe)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount, instance]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        get_resource_string(99999, instance, L"fallback");
+                        successCount++;
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+
+        // Kernel32 resource tests (has known resources)
+        TEST_METHOD(GetResourceString_Kernel32_DoesNotCrash)
+        {
+            HMODULE kernel32 = GetModuleHandleW(L"kernel32.dll");
+            if (kernel32)
+            {
+                // Kernel32 has resources, but we don't know exact IDs
+                // Just verify it doesn't crash
+                get_resource_string(1, kernel32, L"fallback");
+                get_resource_string(100, kernel32, L"fallback");
+                get_resource_string(1000, kernel32, L"fallback");
+            }
+            Assert::IsTrue(true);
+        }
+
+        // Performance test
+        TEST_METHOD(GetResourceString_Performance_Acceptable)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+
+            auto start = std::chrono::high_resolution_clock::now();
+
+            for (int i = 0; i < 1000; ++i)
+            {
+                get_resource_string(99999, instance, L"fallback");
+            }
+
+            auto end = std::chrono::high_resolution_clock::now();
+            auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
+
+            // 1000 lookups should complete in under 1 second
+            Assert::IsTrue(duration.count() < 1000);
+        }
+
+        // Edge case tests
+        TEST_METHOD(GetResourceString_ZeroId_DoesNotCrash)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+            auto result = get_resource_string(0, instance, L"fallback");
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(GetResourceString_MaxUintId_DoesNotCrash)
+        {
+            HINSTANCE instance = GetModuleHandleW(nullptr);
+            auto result = get_resource_string(UINT_MAX, instance, L"fallback");
+            Assert::IsTrue(true);
+        }
+
+    };
+}

src/common/UnitTests-CommonUtils/Serialized.Tests.cpp

@@ -0,0 +1,286 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <serialized.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(SerializedTests)
+    {
+    public:
+        // Basic Read tests
+        TEST_METHOD(Read_DefaultState_ReturnsDefaultValue)
+        {
+            Serialized<int> s;
+            int value = -1;
+            s.Read([&value](const int& v) {
+                value = v;
+            });
+            Assert::AreEqual(0, value); // Default constructed int is 0
+        }
+
+        TEST_METHOD(Read_StringType_ReturnsEmpty)
+        {
+            Serialized<std::string> s;
+            std::string value = "initial";
+            s.Read([&value](const std::string& v) {
+                value = v;
+            });
+            Assert::AreEqual(std::string(""), value);
+        }
+
+        // Basic Access tests
+        TEST_METHOD(Access_ModifyValue_ValueIsModified)
+        {
+            Serialized<int> s;
+            s.Access([](int& v) {
+                v = 42;
+            });
+
+            int value = 0;
+            s.Read([&value](const int& v) {
+                value = v;
+            });
+            Assert::AreEqual(42, value);
+        }
+
+        TEST_METHOD(Access_ModifyString_StringIsModified)
+        {
+            Serialized<std::string> s;
+            s.Access([](std::string& v) {
+                v = "hello";
+            });
+
+            std::string value;
+            s.Read([&value](const std::string& v) {
+                value = v;
+            });
+            Assert::AreEqual(std::string("hello"), value);
+        }
+
+        TEST_METHOD(Access_MultipleModifications_LastValuePersists)
+        {
+            Serialized<int> s;
+            s.Access([](int& v) { v = 1; });
+            s.Access([](int& v) { v = 2; });
+            s.Access([](int& v) { v = 3; });
+
+            int value = 0;
+            s.Read([&value](const int& v) {
+                value = v;
+            });
+            Assert::AreEqual(3, value);
+        }
+
+        // Reset tests
+        TEST_METHOD(Reset_AfterModification_ReturnsDefault)
+        {
+            Serialized<int> s;
+            s.Access([](int& v) { v = 42; });
+            s.Reset();
+
+            int value = -1;
+            s.Read([&value](const int& v) {
+                value = v;
+            });
+            Assert::AreEqual(0, value);
+        }
+
+        TEST_METHOD(Reset_String_ReturnsEmpty)
+        {
+            Serialized<std::string> s;
+            s.Access([](std::string& v) { v = "hello"; });
+            s.Reset();
+
+            std::string value = "initial";
+            s.Read([&value](const std::string& v) {
+                value = v;
+            });
+            Assert::AreEqual(std::string(""), value);
+        }
+
+        // Complex type tests
+        TEST_METHOD(Serialized_VectorType_Works)
+        {
+            Serialized<std::vector<int>> s;
+            s.Access([](std::vector<int>& v) {
+                v.push_back(1);
+                v.push_back(2);
+                v.push_back(3);
+            });
+
+            size_t size = 0;
+            int sum = 0;
+            s.Read([&size, &sum](const std::vector<int>& v) {
+                size = v.size();
+                for (int i : v) sum += i;
+            });
+
+            Assert::AreEqual(static_cast<size_t>(3), size);
+            Assert::AreEqual(6, sum);
+        }
+
+        TEST_METHOD(Serialized_MapType_Works)
+        {
+            Serialized<std::map<std::string, int>> s;
+            s.Access([](std::map<std::string, int>& v) {
+                v["one"] = 1;
+                v["two"] = 2;
+            });
+
+            int value = 0;
+            s.Read([&value](const std::map<std::string, int>& v) {
+                auto it = v.find("two");
+                if (it != v.end()) {
+                    value = it->second;
+                }
+            });
+
+            Assert::AreEqual(2, value);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(ThreadSafety_ConcurrentReads_NoDataRace)
+        {
+            Serialized<int> s;
+            s.Access([](int& v) { v = 42; });
+
+            std::atomic<int> readCount{ 0 };
+            std::vector<std::thread> threads;
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&s, &readCount]() {
+                    for (int j = 0; j < 100; ++j)
+                    {
+                        s.Read([&readCount](const int& v) {
+                            if (v == 42) {
+                                readCount++;
+                            }
+                        });
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(1000, readCount.load());
+        }
+
+        TEST_METHOD(ThreadSafety_ConcurrentAccessAndRead_NoDataRace)
+        {
+            Serialized<int> s;
+            std::atomic<bool> done{ false };
+            std::atomic<int> accessCount{ 0 };
+            std::atomic<int> readersReady{ 0 };
+            std::atomic<bool> start{ false };
+
+            // Writer thread
+            std::thread writer([&s, &done, &accessCount, &readersReady, &start]() {
+                while (readersReady.load() < 5)
+                {
+                    std::this_thread::yield();
+                }
+                start = true;
+                for (int i = 0; i < 100; ++i)
+                {
+                    s.Access([i](int& v) {
+                        v = i;
+                    });
+                    accessCount++;
+                }
+                done = true;
+            });
+
+            // Reader threads
+            std::vector<std::thread> readers;
+            std::atomic<int> readAttempts{ 0 };
+
+            for (int i = 0; i < 5; ++i)
+            {
+                readers.emplace_back([&s, &done, &readAttempts, &readersReady, &start]() {
+                    readersReady++;
+                    while (!start)
+                    {
+                        std::this_thread::yield();
+                    }
+                    while (!done)
+                    {
+                        s.Read([](const int& v) {
+                            // Just read the value
+                            (void)v;
+                        });
+                        readAttempts++;
+                    }
+                });
+            }
+
+            writer.join();
+            for (auto& t : readers)
+            {
+                t.join();
+            }
+
+            // Verify all access calls completed
+            Assert::AreEqual(100, accessCount.load());
+            // Verify reads happened
+            Assert::IsTrue(readAttempts > 0);
+        }
+
+        // Struct type test
+        TEST_METHOD(Serialized_StructType_Works)
+        {
+            struct TestStruct
+            {
+                int x = 0;
+                std::string name;
+            };
+
+            Serialized<TestStruct> s;
+            s.Access([](TestStruct& v) {
+                v.x = 10;
+                v.name = "test";
+            });
+
+            int x = 0;
+            std::string name;
+            s.Read([&x, &name](const TestStruct& v) {
+                x = v.x;
+                name = v.name;
+            });
+
+            Assert::AreEqual(10, x);
+            Assert::AreEqual(std::string("test"), name);
+        }
+
+        TEST_METHOD(Reset_StructType_ResetsToDefault)
+        {
+            struct TestStruct
+            {
+                int x = 0;
+                std::string name;
+            };
+
+            Serialized<TestStruct> s;
+            s.Access([](TestStruct& v) {
+                v.x = 10;
+                v.name = "test";
+            });
+            s.Reset();
+
+            int x = -1;
+            std::string name = "not empty";
+            s.Read([&x, &name](const TestStruct& v) {
+                x = v.x;
+                name = v.name;
+            });
+
+            Assert::AreEqual(0, x);
+            Assert::AreEqual(std::string(""), name);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/StringUtils.Tests.cpp

@@ -0,0 +1,283 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <string_utils.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(StringUtilsTests)
+    {
+    public:
+        // left_trim tests
+        TEST_METHOD(LeftTrim_EmptyString_ReturnsEmpty)
+        {
+            std::string_view input = "";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view(""), result);
+        }
+
+        TEST_METHOD(LeftTrim_NoWhitespace_ReturnsOriginal)
+        {
+            std::string_view input = "hello";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(LeftTrim_LeadingSpaces_TrimsSpaces)
+        {
+            std::string_view input = "   hello";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(LeftTrim_LeadingTabs_TrimsTabs)
+        {
+            std::string_view input = "\t\thello";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(LeftTrim_LeadingNewlines_TrimsNewlines)
+        {
+            std::string_view input = "\r\n\nhello";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(LeftTrim_MixedWhitespace_TrimsAll)
+        {
+            std::string_view input = " \t\r\nhello";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(LeftTrim_TrailingWhitespace_PreservesTrailing)
+        {
+            std::string_view input = "   hello   ";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view("hello   "), result);
+        }
+
+        TEST_METHOD(LeftTrim_OnlyWhitespace_ReturnsEmpty)
+        {
+            std::string_view input = "   \t\r\n";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::string_view(""), result);
+        }
+
+        TEST_METHOD(LeftTrim_CustomChars_TrimsSpecified)
+        {
+            std::string_view input = "xxxhello";
+            auto result = left_trim(input, std::string_view("x"));
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(LeftTrim_WideString_Works)
+        {
+            std::wstring_view input = L"   hello";
+            auto result = left_trim(input);
+            Assert::AreEqual(std::wstring_view(L"hello"), result);
+        }
+
+        // right_trim tests
+        TEST_METHOD(RightTrim_EmptyString_ReturnsEmpty)
+        {
+            std::string_view input = "";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view(""), result);
+        }
+
+        TEST_METHOD(RightTrim_NoWhitespace_ReturnsOriginal)
+        {
+            std::string_view input = "hello";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(RightTrim_TrailingSpaces_TrimsSpaces)
+        {
+            std::string_view input = "hello   ";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(RightTrim_TrailingTabs_TrimsTabs)
+        {
+            std::string_view input = "hello\t\t";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(RightTrim_TrailingNewlines_TrimsNewlines)
+        {
+            std::string_view input = "hello\r\n\n";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(RightTrim_LeadingWhitespace_PreservesLeading)
+        {
+            std::string_view input = "   hello   ";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view("   hello"), result);
+        }
+
+        TEST_METHOD(RightTrim_OnlyWhitespace_ReturnsEmpty)
+        {
+            std::string_view input = "   \t\r\n";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::string_view(""), result);
+        }
+
+        TEST_METHOD(RightTrim_CustomChars_TrimsSpecified)
+        {
+            std::string_view input = "helloxxx";
+            auto result = right_trim(input, std::string_view("x"));
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(RightTrim_WideString_Works)
+        {
+            std::wstring_view input = L"hello   ";
+            auto result = right_trim(input);
+            Assert::AreEqual(std::wstring_view(L"hello"), result);
+        }
+
+        // trim tests
+        TEST_METHOD(Trim_EmptyString_ReturnsEmpty)
+        {
+            std::string_view input = "";
+            auto result = trim(input);
+            Assert::AreEqual(std::string_view(""), result);
+        }
+
+        TEST_METHOD(Trim_NoWhitespace_ReturnsOriginal)
+        {
+            std::string_view input = "hello";
+            auto result = trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(Trim_BothSides_TrimsBoth)
+        {
+            std::string_view input = "   hello   ";
+            auto result = trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(Trim_MixedWhitespace_TrimsAll)
+        {
+            std::string_view input = " \t\r\nhello \t\r\n";
+            auto result = trim(input);
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(Trim_InternalWhitespace_Preserved)
+        {
+            std::string_view input = "   hello world   ";
+            auto result = trim(input);
+            Assert::AreEqual(std::string_view("hello world"), result);
+        }
+
+        TEST_METHOD(Trim_OnlyWhitespace_ReturnsEmpty)
+        {
+            std::string_view input = "   \t\r\n   ";
+            auto result = trim(input);
+            Assert::AreEqual(std::string_view(""), result);
+        }
+
+        TEST_METHOD(Trim_CustomChars_TrimsSpecified)
+        {
+            std::string_view input = "xxxhelloxxx";
+            auto result = trim(input, std::string_view("x"));
+            Assert::AreEqual(std::string_view("hello"), result);
+        }
+
+        TEST_METHOD(Trim_WideString_Works)
+        {
+            std::wstring_view input = L"   hello   ";
+            auto result = trim(input);
+            Assert::AreEqual(std::wstring_view(L"hello"), result);
+        }
+
+        // replace_chars tests
+        TEST_METHOD(ReplaceChars_EmptyString_NoChange)
+        {
+            std::string s = "";
+            replace_chars(s, std::string_view("abc"), 'x');
+            Assert::AreEqual(std::string(""), s);
+        }
+
+        TEST_METHOD(ReplaceChars_NoMatchingChars_NoChange)
+        {
+            std::string s = "hello";
+            replace_chars(s, std::string_view("xyz"), '_');
+            Assert::AreEqual(std::string("hello"), s);
+        }
+
+        TEST_METHOD(ReplaceChars_SingleChar_Replaces)
+        {
+            std::string s = "hello";
+            replace_chars(s, std::string_view("l"), '_');
+            Assert::AreEqual(std::string("he__o"), s);
+        }
+
+        TEST_METHOD(ReplaceChars_MultipleChars_ReplacesAll)
+        {
+            std::string s = "hello world";
+            replace_chars(s, std::string_view("lo"), '_');
+            Assert::AreEqual(std::string("he___ w_r_d"), s);
+        }
+
+        TEST_METHOD(ReplaceChars_WideString_Works)
+        {
+            std::wstring s = L"hello";
+            replace_chars(s, std::wstring_view(L"l"), L'_');
+            Assert::AreEqual(std::wstring(L"he__o"), s);
+        }
+
+        // unwide tests
+        TEST_METHOD(Unwide_EmptyString_ReturnsEmpty)
+        {
+            std::wstring input = L"";
+            auto result = unwide(input);
+            Assert::AreEqual(std::string(""), result);
+        }
+
+        TEST_METHOD(Unwide_AsciiString_Converts)
+        {
+            std::wstring input = L"hello";
+            auto result = unwide(input);
+            Assert::AreEqual(std::string("hello"), result);
+        }
+
+        TEST_METHOD(Unwide_WithNumbers_Converts)
+        {
+            std::wstring input = L"test123";
+            auto result = unwide(input);
+            Assert::AreEqual(std::string("test123"), result);
+        }
+
+        TEST_METHOD(Unwide_WithSpecialChars_Converts)
+        {
+            std::wstring input = L"test!@#$%";
+            auto result = unwide(input);
+            Assert::AreEqual(std::string("test!@#$%"), result);
+        }
+
+        TEST_METHOD(Unwide_MixedCase_PreservesCase)
+        {
+            std::wstring input = L"HeLLo WoRLd";
+            auto result = unwide(input);
+            Assert::AreEqual(std::string("HeLLo WoRLd"), result);
+        }
+
+        TEST_METHOD(Unwide_LongString_Works)
+        {
+            std::wstring input = L"This is a longer string with multiple words and punctuation!";
+            auto result = unwide(input);
+            Assert::AreEqual(std::string("This is a longer string with multiple words and punctuation!"), result);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/TestHelpers.h

@@ -0,0 +1,192 @@
+#pragma once
+
+#include "pch.h"
+#include <string>
+#include <filesystem>
+#include <fstream>
+#include <random>
+
+namespace TestHelpers
+{
+    // RAII helper for creating and cleaning up temporary files
+    class TempFile
+    {
+    public:
+        TempFile(const std::wstring& content = L"", const std::wstring& extension = L".txt")
+        {
+            wchar_t tempPath[MAX_PATH];
+            GetTempPathW(MAX_PATH, tempPath);
+
+            // Generate a unique filename
+            std::random_device rd;
+            std::mt19937 gen(rd());
+            std::uniform_int_distribution<> dis(10000, 99999);
+
+            m_path = std::wstring(tempPath) + L"test_" + std::to_wstring(dis(gen)) + extension;
+
+            if (!content.empty())
+            {
+                std::wofstream file(m_path);
+                file << content;
+            }
+        }
+
+        ~TempFile()
+        {
+            if (std::filesystem::exists(m_path))
+            {
+                std::filesystem::remove(m_path);
+            }
+        }
+
+        TempFile(const TempFile&) = delete;
+        TempFile& operator=(const TempFile&) = delete;
+
+        const std::wstring& path() const { return m_path; }
+
+        void write(const std::string& content)
+        {
+            std::ofstream file(m_path, std::ios::binary);
+            file << content;
+        }
+
+        void write(const std::wstring& content)
+        {
+            std::wofstream file(m_path);
+            file << content;
+        }
+
+        std::wstring read()
+        {
+            std::wifstream file(m_path);
+            return std::wstring((std::istreambuf_iterator<wchar_t>(file)),
+                               std::istreambuf_iterator<wchar_t>());
+        }
+
+    private:
+        std::wstring m_path;
+    };
+
+    // RAII helper for creating and cleaning up temporary directories
+    class TempDirectory
+    {
+    public:
+        TempDirectory()
+        {
+            wchar_t tempPath[MAX_PATH];
+            GetTempPathW(MAX_PATH, tempPath);
+
+            std::random_device rd;
+            std::mt19937 gen(rd());
+            std::uniform_int_distribution<> dis(10000, 99999);
+
+            m_path = std::wstring(tempPath) + L"testdir_" + std::to_wstring(dis(gen));
+            std::filesystem::create_directories(m_path);
+        }
+
+        ~TempDirectory()
+        {
+            if (std::filesystem::exists(m_path))
+            {
+                std::filesystem::remove_all(m_path);
+            }
+        }
+
+        TempDirectory(const TempDirectory&) = delete;
+        TempDirectory& operator=(const TempDirectory&) = delete;
+
+        const std::wstring& path() const { return m_path; }
+
+    private:
+        std::wstring m_path;
+    };
+
+    // Registry test key path - use HKCU for non-elevated tests
+    inline const std::wstring TestRegistryPath = L"Software\\PowerToys\\UnitTests";
+
+    // RAII helper for registry key creation/cleanup
+    class TestRegistryKey
+    {
+    public:
+        TestRegistryKey(const std::wstring& subKey = L"")
+        {
+            m_path = TestRegistryPath;
+            if (!subKey.empty())
+            {
+                m_path += L"\\" + subKey;
+            }
+
+            HKEY key;
+            if (RegCreateKeyExW(HKEY_CURRENT_USER, m_path.c_str(), 0, nullptr,
+                               REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, nullptr,
+                               &key, nullptr) == ERROR_SUCCESS)
+            {
+                RegCloseKey(key);
+                m_created = true;
+            }
+        }
+
+        ~TestRegistryKey()
+        {
+            if (m_created)
+            {
+                RegDeleteTreeW(HKEY_CURRENT_USER, m_path.c_str());
+            }
+        }
+
+        TestRegistryKey(const TestRegistryKey&) = delete;
+        TestRegistryKey& operator=(const TestRegistryKey&) = delete;
+
+        bool isValid() const { return m_created; }
+        const std::wstring& path() const { return m_path; }
+
+        bool setStringValue(const std::wstring& name, const std::wstring& value)
+        {
+            HKEY key;
+            if (RegOpenKeyExW(HKEY_CURRENT_USER, m_path.c_str(), 0, KEY_SET_VALUE, &key) != ERROR_SUCCESS)
+            {
+                return false;
+            }
+
+            auto result = RegSetValueExW(key, name.c_str(), 0, REG_SZ,
+                                        reinterpret_cast<const BYTE*>(value.c_str()),
+                                        static_cast<DWORD>((value.length() + 1) * sizeof(wchar_t)));
+            RegCloseKey(key);
+            return result == ERROR_SUCCESS;
+        }
+
+        bool setDwordValue(const std::wstring& name, DWORD value)
+        {
+            HKEY key;
+            if (RegOpenKeyExW(HKEY_CURRENT_USER, m_path.c_str(), 0, KEY_SET_VALUE, &key) != ERROR_SUCCESS)
+            {
+                return false;
+            }
+
+            auto result = RegSetValueExW(key, name.c_str(), 0, REG_DWORD,
+                                        reinterpret_cast<const BYTE*>(&value), sizeof(DWORD));
+            RegCloseKey(key);
+            return result == ERROR_SUCCESS;
+        }
+
+    private:
+        std::wstring m_path;
+        bool m_created = false;
+    };
+
+    // Helper to wait for a condition with timeout
+    template<typename Predicate>
+    bool WaitFor(Predicate pred, std::chrono::milliseconds timeout = std::chrono::milliseconds(5000))
+    {
+        auto start = std::chrono::steady_clock::now();
+        while (!pred())
+        {
+            if (std::chrono::steady_clock::now() - start > timeout)
+            {
+                return false;
+            }
+            std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        }
+        return true;
+    }
+}

src/common/UnitTests-CommonUtils/TestStubs.cpp

@@ -0,0 +1,14 @@
+#include "pch.h"
+#include <common/logger/logger.h>
+#include <common/SettingsAPI/settings_helpers.h>
+#include <spdlog/sinks/null_sink.h>
+
+std::shared_ptr<spdlog::logger> Logger::logger = spdlog::null_logger_mt("Common.Utils.UnitTests");
+
+namespace PTSettingsHelper
+{
+    std::wstring get_root_save_folder_location()
+    {
+        return L"";
+    }
+}

src/common/UnitTests-CommonUtils/Threading.Tests.cpp

@@ -0,0 +1,336 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <OnThreadExecutor.h>
+#include <EventWaiter.h>
+#include <EventLocker.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(OnThreadExecutorTests)
+    {
+    public:
+        TEST_METHOD(Constructor_CreatesInstance)
+        {
+            OnThreadExecutor executor;
+            // Should not crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(Submit_SingleTask_Executes)
+        {
+            OnThreadExecutor executor;
+            std::atomic<bool> executed{ false };
+
+            auto future = executor.submit(OnThreadExecutor::task_t([&executed]() {
+                executed = true;
+            }));
+
+            future.wait();
+            Assert::IsTrue(executed);
+        }
+
+        TEST_METHOD(Submit_MultipleTasks_ExecutesAll)
+        {
+            OnThreadExecutor executor;
+            std::atomic<int> counter{ 0 };
+
+            std::vector<std::future<void>> futures;
+            for (int i = 0; i < 10; ++i)
+            {
+                futures.push_back(executor.submit(OnThreadExecutor::task_t([&counter]() {
+                    counter++;
+                })));
+            }
+
+            for (auto& f : futures)
+            {
+                f.wait();
+            }
+
+            Assert::AreEqual(10, counter.load());
+        }
+
+        TEST_METHOD(Submit_TasksExecuteInOrder)
+        {
+            OnThreadExecutor executor;
+            std::vector<int> order;
+            std::mutex orderMutex;
+
+            std::vector<std::future<void>> futures;
+            for (int i = 0; i < 5; ++i)
+            {
+                futures.push_back(executor.submit(OnThreadExecutor::task_t([&order, &orderMutex, i]() {
+                    std::lock_guard lock(orderMutex);
+                    order.push_back(i);
+                })));
+            }
+
+            for (auto& f : futures)
+            {
+                f.wait();
+            }
+
+            Assert::AreEqual(static_cast<size_t>(5), order.size());
+            for (int i = 0; i < 5; ++i)
+            {
+                Assert::AreEqual(i, order[i]);
+            }
+        }
+
+        TEST_METHOD(Submit_TaskReturnsResult)
+        {
+            OnThreadExecutor executor;
+            std::atomic<int> result{ 0 };
+
+            auto future = executor.submit(OnThreadExecutor::task_t([&result]() {
+                result = 42;
+            }));
+
+            future.wait();
+            Assert::AreEqual(42, result.load());
+        }
+
+        TEST_METHOD(Cancel_ClearsPendingTasks)
+        {
+            OnThreadExecutor executor;
+            std::atomic<int> counter{ 0 };
+
+            // Submit a slow task first
+            executor.submit(OnThreadExecutor::task_t([&counter]() {
+                std::this_thread::sleep_for(std::chrono::milliseconds(100));
+                counter++;
+            }));
+
+            // Submit more tasks
+            for (int i = 0; i < 5; ++i)
+            {
+                executor.submit(OnThreadExecutor::task_t([&counter]() {
+                    counter++;
+                }));
+            }
+
+            // Cancel pending tasks
+            executor.cancel();
+
+            // Wait a bit for any running task to complete
+            std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+            // Not all tasks should have executed
+            Assert::IsTrue(counter < 6);
+        }
+
+        TEST_METHOD(Destructor_WaitsForCompletion)
+        {
+            std::atomic<bool> completed{ false };
+            std::future<void> future;
+
+            {
+                OnThreadExecutor executor;
+                future = executor.submit(OnThreadExecutor::task_t([&completed]() {
+                    std::this_thread::sleep_for(std::chrono::milliseconds(50));
+                    completed = true;
+                }));
+                future.wait();
+            } // Destructor no longer required to wait for completion
+
+            Assert::IsTrue(completed);
+        }
+
+        TEST_METHOD(Submit_AfterCancel_StillWorks)
+        {
+            OnThreadExecutor executor;
+            std::atomic<int> counter{ 0 };
+
+            executor.submit(OnThreadExecutor::task_t([&counter]() {
+                counter++;
+            }));
+            executor.cancel();
+
+            auto future = executor.submit(OnThreadExecutor::task_t([&counter]() {
+                counter = 42;
+            }));
+            future.wait();
+
+            Assert::AreEqual(42, counter.load());
+        }
+    };
+
+    TEST_CLASS(EventWaiterTests)
+    {
+    public:
+        TEST_METHOD(Constructor_CreatesInstance)
+        {
+            EventWaiter waiter;
+            Assert::IsFalse(waiter.is_listening());
+        }
+
+        TEST_METHOD(Start_ValidEvent_ReturnsTrue)
+        {
+            EventWaiter waiter;
+            bool result = waiter.start(L"TestEvent_Start", [](DWORD) {});
+            Assert::IsTrue(result);
+            Assert::IsTrue(waiter.is_listening());
+            waiter.stop();
+        }
+
+        TEST_METHOD(Start_AlreadyListening_ReturnsFalse)
+        {
+            EventWaiter waiter;
+            waiter.start(L"TestEvent_Double1", [](DWORD) {});
+            bool result = waiter.start(L"TestEvent_Double2", [](DWORD) {});
+            Assert::IsFalse(result);
+            waiter.stop();
+        }
+
+        TEST_METHOD(Stop_WhileListening_StopsListening)
+        {
+            EventWaiter waiter;
+            waiter.start(L"TestEvent_Stop", [](DWORD) {});
+            Assert::IsTrue(waiter.is_listening());
+
+            waiter.stop();
+            Assert::IsFalse(waiter.is_listening());
+        }
+
+        TEST_METHOD(Stop_WhenNotListening_DoesNotCrash)
+        {
+            EventWaiter waiter;
+            waiter.stop(); // Should not crash
+            Assert::IsFalse(waiter.is_listening());
+        }
+
+        TEST_METHOD(Stop_CalledMultipleTimes_DoesNotCrash)
+        {
+            EventWaiter waiter;
+            waiter.start(L"TestEvent_MultiStop", [](DWORD) {});
+            waiter.stop();
+            waiter.stop();
+            waiter.stop();
+            Assert::IsFalse(waiter.is_listening());
+        }
+
+        TEST_METHOD(Callback_EventSignaled_CallsCallback)
+        {
+            EventWaiter waiter;
+            std::atomic<bool> called{ false };
+            std::atomic<DWORD> errorCode{ 0xFFFFFFFF };
+
+            // Create a named event we can signal
+            std::wstring eventName = L"TestEvent_Callback_" + std::to_wstring(GetCurrentProcessId());
+            HANDLE signalEvent = CreateEventW(nullptr, FALSE, FALSE, eventName.c_str());
+            Assert::IsNotNull(signalEvent);
+
+            waiter.start(eventName, [&called, &errorCode](DWORD err) {
+                errorCode = err;
+                called = true;
+            });
+
+            // Signal the event
+            SetEvent(signalEvent);
+
+            // Wait for callback
+            bool waitResult = TestHelpers::WaitFor([&called]() { return called.load(); }, std::chrono::milliseconds(1000));
+
+            waiter.stop();
+            CloseHandle(signalEvent);
+
+            Assert::IsTrue(waitResult);
+            Assert::AreEqual(static_cast<DWORD>(ERROR_SUCCESS), errorCode.load());
+        }
+
+        TEST_METHOD(Destructor_StopsListening)
+        {
+            std::atomic<bool> isListening{ false };
+            {
+                EventWaiter waiter;
+                waiter.start(L"TestEvent_Destructor", [](DWORD) {});
+                isListening = waiter.is_listening();
+            }
+            // After destruction, the waiter should have stopped
+            Assert::IsTrue(isListening);
+        }
+
+        TEST_METHOD(IsListening_InitialState_ReturnsFalse)
+        {
+            EventWaiter waiter;
+            Assert::IsFalse(waiter.is_listening());
+        }
+
+        TEST_METHOD(IsListening_AfterStart_ReturnsTrue)
+        {
+            EventWaiter waiter;
+            waiter.start(L"TestEvent_IsListening", [](DWORD) {});
+            Assert::IsTrue(waiter.is_listening());
+            waiter.stop();
+        }
+
+        TEST_METHOD(IsListening_AfterStop_ReturnsFalse)
+        {
+            EventWaiter waiter;
+            waiter.start(L"TestEvent_AfterStop", [](DWORD) {});
+            waiter.stop();
+            Assert::IsFalse(waiter.is_listening());
+        }
+    };
+
+    TEST_CLASS(EventLockerTests)
+    {
+    public:
+        TEST_METHOD(Get_ValidEventName_ReturnsLocker)
+        {
+            std::wstring eventName = L"TestEventLocker_" + std::to_wstring(GetCurrentProcessId());
+            auto locker = EventLocker::Get(eventName);
+            Assert::IsTrue(locker.has_value());
+        }
+
+        TEST_METHOD(Get_UniqueNames_CreatesSeparateLockers)
+        {
+            auto locker1 = EventLocker::Get(L"TestEventLocker1_" + std::to_wstring(GetCurrentProcessId()));
+            auto locker2 = EventLocker::Get(L"TestEventLocker2_" + std::to_wstring(GetCurrentProcessId()));
+            Assert::IsTrue(locker1.has_value());
+            Assert::IsTrue(locker2.has_value());
+        }
+
+        TEST_METHOD(Destructor_CleansUpHandle)
+        {
+            std::wstring eventName = L"TestEventLockerCleanup_" + std::to_wstring(GetCurrentProcessId());
+            {
+                auto locker = EventLocker::Get(eventName);
+                Assert::IsTrue(locker.has_value());
+            }
+            // After destruction, the event should be cleaned up
+            // Creating a new one should succeed
+            auto newLocker = EventLocker::Get(eventName);
+            Assert::IsTrue(newLocker.has_value());
+        }
+
+        TEST_METHOD(MoveConstructor_TransfersOwnership)
+        {
+            std::wstring eventName = L"TestEventLockerMove_" + std::to_wstring(GetCurrentProcessId());
+            auto locker1 = EventLocker::Get(eventName);
+            Assert::IsTrue(locker1.has_value());
+
+            EventLocker locker2 = std::move(*locker1);
+            // Move should transfer ownership without crash
+            Assert::IsTrue(true);
+        }
+
+        TEST_METHOD(MoveAssignment_TransfersOwnership)
+        {
+            std::wstring eventName1 = L"TestEventLockerMoveAssign1_" + std::to_wstring(GetCurrentProcessId());
+            std::wstring eventName2 = L"TestEventLockerMoveAssign2_" + std::to_wstring(GetCurrentProcessId());
+
+            auto locker1 = EventLocker::Get(eventName1);
+            auto locker2 = EventLocker::Get(eventName2);
+
+            Assert::IsTrue(locker1.has_value());
+            Assert::IsTrue(locker2.has_value());
+
+            *locker1 = std::move(*locker2);
+            // Should not crash
+            Assert::IsTrue(true);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/TimeUtils.Tests.cpp

@@ -0,0 +1,248 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <timeutil.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(TimeUtilsTests)
+    {
+    public:
+        // to_string tests
+        TEST_METHOD(ToString_ZeroTime_ReturnsZero)
+        {
+            time_t t = 0;
+            auto result = timeutil::to_string(t);
+            Assert::AreEqual(std::wstring(L"0"), result);
+        }
+
+        TEST_METHOD(ToString_PositiveTime_ReturnsString)
+        {
+            time_t t = 1234567890;
+            auto result = timeutil::to_string(t);
+            Assert::AreEqual(std::wstring(L"1234567890"), result);
+        }
+
+        TEST_METHOD(ToString_LargeTime_ReturnsString)
+        {
+            time_t t = 1700000000;
+            auto result = timeutil::to_string(t);
+            Assert::AreEqual(std::wstring(L"1700000000"), result);
+        }
+
+        // from_string tests
+        TEST_METHOD(FromString_ZeroString_ReturnsZero)
+        {
+            auto result = timeutil::from_string(L"0");
+            Assert::IsTrue(result.has_value());
+            Assert::AreEqual(static_cast<time_t>(0), result.value());
+        }
+
+        TEST_METHOD(FromString_ValidNumber_ReturnsTime)
+        {
+            auto result = timeutil::from_string(L"1234567890");
+            Assert::IsTrue(result.has_value());
+            Assert::AreEqual(static_cast<time_t>(1234567890), result.value());
+        }
+
+        TEST_METHOD(FromString_InvalidString_ReturnsNullopt)
+        {
+            auto result = timeutil::from_string(L"invalid");
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(FromString_EmptyString_ReturnsNullopt)
+        {
+            auto result = timeutil::from_string(L"");
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(FromString_MixedAlphaNumeric_ReturnsNullopt)
+        {
+            auto result = timeutil::from_string(L"123abc");
+            Assert::IsFalse(result.has_value());
+        }
+
+        TEST_METHOD(FromString_NegativeNumber_ReturnsNullopt)
+        {
+            auto result = timeutil::from_string(L"-1");
+            Assert::IsFalse(result.has_value());
+        }
+
+        // Roundtrip test
+        TEST_METHOD(ToStringFromString_Roundtrip_Works)
+        {
+            time_t original = 1609459200; // 2021-01-01 00:00:00 UTC
+            auto str = timeutil::to_string(original);
+            auto result = timeutil::from_string(str);
+            Assert::IsTrue(result.has_value());
+            Assert::AreEqual(original, result.value());
+        }
+
+        // now tests
+        TEST_METHOD(Now_ReturnsReasonableTime)
+        {
+            auto result = timeutil::now();
+            // Should be after 2020 and before 2100
+            Assert::IsTrue(result > 1577836800); // 2020-01-01
+            Assert::IsTrue(result < 4102444800); // 2100-01-01
+        }
+
+        TEST_METHOD(Now_TwoCallsAreCloseInTime)
+        {
+            auto first = timeutil::now();
+            std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            auto second = timeutil::now();
+            // Difference should be less than 2 seconds
+            Assert::IsTrue(second >= first);
+            Assert::IsTrue(second - first < 2);
+        }
+
+        // diff::in_seconds tests
+        TEST_METHOD(DiffInSeconds_SameTime_ReturnsZero)
+        {
+            time_t t = 1000000;
+            auto result = timeutil::diff::in_seconds(t, t);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        TEST_METHOD(DiffInSeconds_OneDifference_ReturnsOne)
+        {
+            time_t to = 1000001;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_seconds(to, from);
+            Assert::AreEqual(static_cast<int64_t>(1), result);
+        }
+
+        TEST_METHOD(DiffInSeconds_60Seconds_Returns60)
+        {
+            time_t to = 1000060;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_seconds(to, from);
+            Assert::AreEqual(static_cast<int64_t>(60), result);
+        }
+
+        TEST_METHOD(DiffInSeconds_NegativeDiff_ReturnsNegative)
+        {
+            time_t to = 1000000;
+            time_t from = 1000060;
+            auto result = timeutil::diff::in_seconds(to, from);
+            Assert::AreEqual(static_cast<int64_t>(-60), result);
+        }
+
+        // diff::in_minutes tests
+        TEST_METHOD(DiffInMinutes_SameTime_ReturnsZero)
+        {
+            time_t t = 1000000;
+            auto result = timeutil::diff::in_minutes(t, t);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        TEST_METHOD(DiffInMinutes_OneMinute_ReturnsOne)
+        {
+            time_t to = 1000060;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_minutes(to, from);
+            Assert::AreEqual(static_cast<int64_t>(1), result);
+        }
+
+        TEST_METHOD(DiffInMinutes_60Minutes_Returns60)
+        {
+            time_t to = 1003600;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_minutes(to, from);
+            Assert::AreEqual(static_cast<int64_t>(60), result);
+        }
+
+        TEST_METHOD(DiffInMinutes_LessThanMinute_ReturnsZero)
+        {
+            time_t to = 1000059;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_minutes(to, from);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        // diff::in_hours tests
+        TEST_METHOD(DiffInHours_SameTime_ReturnsZero)
+        {
+            time_t t = 1000000;
+            auto result = timeutil::diff::in_hours(t, t);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        TEST_METHOD(DiffInHours_OneHour_ReturnsOne)
+        {
+            time_t to = 1003600;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_hours(to, from);
+            Assert::AreEqual(static_cast<int64_t>(1), result);
+        }
+
+        TEST_METHOD(DiffInHours_24Hours_Returns24)
+        {
+            time_t to = 1086400;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_hours(to, from);
+            Assert::AreEqual(static_cast<int64_t>(24), result);
+        }
+
+        TEST_METHOD(DiffInHours_LessThanHour_ReturnsZero)
+        {
+            time_t to = 1003599;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_hours(to, from);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        // diff::in_days tests
+        TEST_METHOD(DiffInDays_SameTime_ReturnsZero)
+        {
+            time_t t = 1000000;
+            auto result = timeutil::diff::in_days(t, t);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        TEST_METHOD(DiffInDays_OneDay_ReturnsOne)
+        {
+            time_t to = 1086400;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_days(to, from);
+            Assert::AreEqual(static_cast<int64_t>(1), result);
+        }
+
+        TEST_METHOD(DiffInDays_7Days_Returns7)
+        {
+            time_t to = 1604800;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_days(to, from);
+            Assert::AreEqual(static_cast<int64_t>(7), result);
+        }
+
+        TEST_METHOD(DiffInDays_LessThanDay_ReturnsZero)
+        {
+            time_t to = 1086399;
+            time_t from = 1000000;
+            auto result = timeutil::diff::in_days(to, from);
+            Assert::AreEqual(static_cast<int64_t>(0), result);
+        }
+
+        // format_as_local tests
+        TEST_METHOD(FormatAsLocal_YearFormat_ReturnsYear)
+        {
+            time_t t = 1609459200; // 2021-01-01 00:00:00 UTC
+            auto result = timeutil::format_as_local("%Y", t);
+            // Result depends on local timezone, but year should be 2020 or 2021
+            Assert::IsTrue(result == "2020" || result == "2021");
+        }
+
+        TEST_METHOD(FormatAsLocal_DateFormat_ReturnsDate)
+        {
+            time_t t = 0; // 1970-01-01 00:00:00 UTC
+            auto result = timeutil::format_as_local("%Y-%m-%d", t);
+            // Result should be a date around 1970-01-01 depending on timezone
+            Assert::IsTrue(result.length() == 10); // YYYY-MM-DD format
+            Assert::IsTrue(result.substr(0, 4) == "1969" || result.substr(0, 4) == "1970");
+        }
+    };
+}

src/common/UnitTests-CommonUtils/UnhandledException.Tests.cpp

@@ -0,0 +1,210 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <UnhandledExceptionHandler.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(UnhandledExceptionTests)
+    {
+    public:
+        // exceptionDescription tests
+        TEST_METHOD(ExceptionDescription_AccessViolation_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_ACCESS_VIOLATION);
+            Assert::IsTrue(result && *result != '\0');
+            // Should contain meaningful description
+            std::string desc{ result };
+            Assert::IsTrue(desc.find("ACCESS") != std::string::npos ||
+                          desc.find("access") != std::string::npos ||
+                          desc.find("violation") != std::string::npos ||
+                          desc.length() > 0);
+        }
+
+        TEST_METHOD(ExceptionDescription_StackOverflow_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_STACK_OVERFLOW);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_DivideByZero_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_INT_DIVIDE_BY_ZERO);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_IllegalInstruction_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_ILLEGAL_INSTRUCTION);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_ArrayBoundsExceeded_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_ARRAY_BOUNDS_EXCEEDED);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_Breakpoint_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_BREAKPOINT);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_SingleStep_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_SINGLE_STEP);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_FloatDivideByZero_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_FLT_DIVIDE_BY_ZERO);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_FloatOverflow_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_FLT_OVERFLOW);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_FloatUnderflow_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_FLT_UNDERFLOW);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_FloatInvalidOperation_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_FLT_INVALID_OPERATION);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_PrivilegedInstruction_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_PRIV_INSTRUCTION);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_InPageError_ReturnsDescription)
+        {
+            auto result = exceptionDescription(EXCEPTION_IN_PAGE_ERROR);
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_UnknownCode_ReturnsDescription)
+        {
+            auto result = exceptionDescription(0x12345678);
+            // Should return something (possibly "Unknown exception" or similar)
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        TEST_METHOD(ExceptionDescription_ZeroCode_ReturnsDescription)
+        {
+            auto result = exceptionDescription(0);
+            // Should handle zero gracefully
+            Assert::IsTrue(result && *result != '\0');
+        }
+
+        // GetFilenameStart tests (if accessible)
+        TEST_METHOD(GetFilenameStart_ValidPath_ReturnsFilename)
+        {
+            wchar_t path[] = L"C:\\folder\\subfolder\\file.exe";
+            int start = GetFilenameStart(path);
+
+            Assert::IsTrue(start >= 0);
+            Assert::AreEqual(std::wstring(L"file.exe"), std::wstring(path + start));
+        }
+
+        TEST_METHOD(GetFilenameStart_NoPath_ReturnsOriginal)
+        {
+            wchar_t path[] = L"file.exe";
+            int start = GetFilenameStart(path);
+
+            Assert::IsTrue(start >= 0);
+            Assert::AreEqual(std::wstring(L"file.exe"), std::wstring(path + start));
+        }
+
+        TEST_METHOD(GetFilenameStart_TrailingBackslash_ReturnsEmpty)
+        {
+            wchar_t path[] = L"C:\\folder\\";
+            int start = GetFilenameStart(path);
+
+            // Should point to empty string after last backslash
+            Assert::IsTrue(start >= 0);
+        }
+
+        TEST_METHOD(GetFilenameStart_NullPath_HandlesGracefully)
+        {
+            // This might crash or return null depending on implementation
+            // Just document the behavior
+            int start = GetFilenameStart(nullptr);
+            (void)start;
+            // Result is implementation-defined for null input
+            Assert::IsTrue(true);
+        }
+
+        // Thread safety tests
+        TEST_METHOD(ExceptionDescription_ThreadSafe)
+        {
+            std::vector<std::thread> threads;
+            std::atomic<int> successCount{ 0 };
+
+            for (int i = 0; i < 10; ++i)
+            {
+                threads.emplace_back([&successCount]() {
+                    for (int j = 0; j < 10; ++j)
+                    {
+                        auto desc = exceptionDescription(EXCEPTION_ACCESS_VIOLATION);
+                        if (desc && *desc != '\0')
+                        {
+                            successCount++;
+                        }
+                    }
+                });
+            }
+
+            for (auto& t : threads)
+            {
+                t.join();
+            }
+
+            Assert::AreEqual(100, successCount.load());
+        }
+
+        // All exception codes test
+        TEST_METHOD(ExceptionDescription_AllCommonCodes_ReturnDescriptions)
+        {
+            std::vector<DWORD> codes = {
+                EXCEPTION_ACCESS_VIOLATION,
+                EXCEPTION_ARRAY_BOUNDS_EXCEEDED,
+                EXCEPTION_BREAKPOINT,
+                EXCEPTION_DATATYPE_MISALIGNMENT,
+                EXCEPTION_FLT_DENORMAL_OPERAND,
+                EXCEPTION_FLT_DIVIDE_BY_ZERO,
+                EXCEPTION_FLT_INEXACT_RESULT,
+                EXCEPTION_FLT_INVALID_OPERATION,
+                EXCEPTION_FLT_OVERFLOW,
+                EXCEPTION_FLT_STACK_CHECK,
+                EXCEPTION_FLT_UNDERFLOW,
+                EXCEPTION_ILLEGAL_INSTRUCTION,
+                EXCEPTION_IN_PAGE_ERROR,
+                EXCEPTION_INT_DIVIDE_BY_ZERO,
+                EXCEPTION_INT_OVERFLOW,
+                EXCEPTION_INVALID_DISPOSITION,
+                EXCEPTION_NONCONTINUABLE_EXCEPTION,
+                EXCEPTION_PRIV_INSTRUCTION,
+                EXCEPTION_SINGLE_STEP,
+                EXCEPTION_STACK_OVERFLOW
+            };
+
+            for (DWORD code : codes)
+            {
+                auto desc = exceptionDescription(code);
+                Assert::IsTrue(desc && *desc != '\0', (L"Empty description for code: " + std::to_wstring(code)).c_str());
+            }
+        }
+    };
+}

src/common/UnitTests-CommonUtils/UnitTests-CommonUtils.rc

@@ -0,0 +1,36 @@
+#include <windows.h>
+#include "resource.h"
+#include "../version/version.h"
+
+1 VERSIONINFO
+FILEVERSION FILE_VERSION
+PRODUCTVERSION PRODUCT_VERSION
+FILEFLAGSMASK VS_FFI_FILEFLAGSMASK
+#ifdef _DEBUG
+FILEFLAGS VS_FF_DEBUG
+#else
+FILEFLAGS 0x0L
+#endif
+FILEOS VOS_NT_WINDOWS32
+FILETYPE VFT_DLL
+FILESUBTYPE VFT2_UNKNOWN
+BEGIN
+    BLOCK "StringFileInfo"
+    BEGIN
+        BLOCK "040904b0" // US English (0x0409), Unicode (0x04B0) charset
+        BEGIN
+            VALUE "CompanyName", COMPANY_NAME
+            VALUE "FileDescription", FILE_DESCRIPTION
+            VALUE "FileVersion", FILE_VERSION_STRING
+            VALUE "InternalName", INTERNAL_NAME
+            VALUE "LegalCopyright", COPYRIGHT_NOTE
+            VALUE "OriginalFilename", ORIGINAL_FILENAME
+            VALUE "ProductName", PRODUCT_NAME
+            VALUE "ProductVersion", PRODUCT_VERSION_STRING
+        END
+    END
+    BLOCK "VarFileInfo"
+    BEGIN
+        VALUE "Translation", 0x409, 1200 // US English (0x0409), Unicode (1200) charset
+    END
+END

src/common/UnitTests-CommonUtils/UnitTests-CommonUtils.vcxproj

@@ -0,0 +1,96 @@
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+  <PropertyGroup Label="Globals">
+    <VCProjectVersion>16.0</VCProjectVersion>
+    <ProjectGuid>{8B5CFB38-CCBA-40A8-AD7A-89C57B070884}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>UnitTestsCommonUtils</RootNamespace>
+    <ProjectSubType>NativeUnitTestProject</ProjectSubType>
+    <ProjectName>Common.Utils.UnitTests</ProjectName>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseOfMfc>false</UseOfMfc>
+    <PlatformToolset>v143</PlatformToolset>
+    <OutDir>$(SolutionDir)$(Platform)\$(Configuration)\tests\UnitTestsCommonUtils\</OutDir>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="Shared">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <AdditionalIncludeDirectories>..\;..\utils;..\Telemetry;..\..\;..\..\..\deps\;..\..\..\deps\spdlog\include;..\..\..\packages\Microsoft.Windows.ImplementationLibrary.1.0.231216.1\include;$(VCInstallDir)UnitTest\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <LanguageStandard>stdcpp23</LanguageStandard>
+      <PreprocessorDefinitions>SPDLOG_WCHAR_TO_UTF8_SUPPORT;SPDLOG_HEADER_ONLY;%(PreprocessorDefinitions)</PreprocessorDefinitions>
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+    <Link>
+      <AdditionalLibraryDirectories>$(VCInstallDir)UnitTest\lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+      <AdditionalDependencies>RuntimeObject.lib;Msi.lib;Shlwapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
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+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="pch.cpp">
+      <PrecompiledHeader Condition="'$(UsePrecompiledHeaders)' != 'false'">Create</PrecompiledHeader>
+    </ClCompile>
+    <ClCompile Include="StringUtils.Tests.cpp" />
+    <ClCompile Include="ColorUtils.Tests.cpp" />
+    <ClCompile Include="TimeUtils.Tests.cpp" />
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+    <ClCompile Include="GameMode.Tests.cpp" />
+    <ClCompile Include="Gpo.Tests.cpp" />
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+    <ClCompile Include="Elevation.Tests.cpp" />
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+    <ClCompile Include="LoggerHelper.Tests.cpp" />
+    <ClCompile Include="ModulesRegistry.Tests.cpp" />
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+    <ClCompile Include="Package.Tests.cpp" />
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+    <ClCompile Include="Resources.Tests.cpp" />
+    <ClCompile Include="TestStubs.cpp" />
+    <ClCompile Include="UnhandledException.Tests.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="pch.h" />
+    <ClInclude Include="resource.h" />
+    <ClInclude Include="TestHelpers.h" />
+  </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="UnitTests-CommonUtils.rc" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="packages.config" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+    <Import Project="..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets" Condition="Exists('..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets')" />
+  </ImportGroup>
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.props')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.props'))" />
+    <Error Condition="!Exists('..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets'))" />
+  </Target>
+</Project>

src/common/UnitTests-CommonUtils/UnitTests-CommonUtils.vcxproj.filters

@@ -0,0 +1,143 @@
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+    </ClCompile>
+    <ClCompile Include="MsiUtils.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+    <ClCompile Include="HttpClient.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+    <ClCompile Include="Resources.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+    <ClCompile Include="LoggerHelper.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+    <ClCompile Include="ComObjectFactory.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+    <ClCompile Include="HDropIterator.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+    <ClCompile Include="UnhandledException.Tests.cpp">
+      <Filter>Source Files\Integration</Filter>
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="pch.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="resource.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="TestHelpers.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+  </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="UnitTests-CommonUtils.rc">
+      <Filter>Resource Files</Filter>
+    </ResourceCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="packages.config" />
+  </ItemGroup>
+</Project>

src/common/UnitTests-CommonUtils/WinApiError.Tests.cpp

@@ -0,0 +1,130 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <winapi_error.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(WinApiErrorTests)
+    {
+    public:
+        // get_last_error_message tests
+        TEST_METHOD(GetLastErrorMessage_Success_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_SUCCESS);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_FileNotFound_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_FILE_NOT_FOUND);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_AccessDenied_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_ACCESS_DENIED);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_PathNotFound_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_PATH_NOT_FOUND);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_InvalidHandle_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_INVALID_HANDLE);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_NotEnoughMemory_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_NOT_ENOUGH_MEMORY);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_InvalidParameter_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_INVALID_PARAMETER);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        // get_last_error_or_default tests
+        TEST_METHOD(GetLastErrorOrDefault_Success_ReturnsMessage)
+        {
+            auto result = get_last_error_or_default(ERROR_SUCCESS);
+            Assert::IsFalse(result.empty());
+        }
+
+        TEST_METHOD(GetLastErrorOrDefault_FileNotFound_ReturnsMessage)
+        {
+            auto result = get_last_error_or_default(ERROR_FILE_NOT_FOUND);
+            Assert::IsFalse(result.empty());
+        }
+
+        TEST_METHOD(GetLastErrorOrDefault_AccessDenied_ReturnsMessage)
+        {
+            auto result = get_last_error_or_default(ERROR_ACCESS_DENIED);
+            Assert::IsFalse(result.empty());
+        }
+
+        TEST_METHOD(GetLastErrorOrDefault_UnknownError_ReturnsEmptyOrMessage)
+        {
+            // For an unknown error code, should return empty string or a default message
+            auto result = get_last_error_or_default(0xFFFFFFFF);
+            // Either empty or has content, both are valid
+            Assert::IsTrue(result.empty() || !result.empty());
+        }
+
+        // Comparison tests
+        TEST_METHOD(BothFunctions_SameError_ProduceSameContent)
+        {
+            auto message = get_last_error_message(ERROR_FILE_NOT_FOUND);
+            auto defaultMessage = get_last_error_or_default(ERROR_FILE_NOT_FOUND);
+
+            Assert::IsTrue(message.has_value());
+            Assert::AreEqual(*message, defaultMessage);
+        }
+
+        TEST_METHOD(BothFunctions_SuccessError_ProduceSameContent)
+        {
+            auto message = get_last_error_message(ERROR_SUCCESS);
+            auto defaultMessage = get_last_error_or_default(ERROR_SUCCESS);
+
+            Assert::IsTrue(message.has_value());
+            Assert::AreEqual(*message, defaultMessage);
+        }
+
+        // Error code specific tests
+        TEST_METHOD(GetLastErrorMessage_SharingViolation_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_SHARING_VIOLATION);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_FileExists_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_FILE_EXISTS);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+
+        TEST_METHOD(GetLastErrorMessage_DirNotEmpty_ReturnsMessage)
+        {
+            auto result = get_last_error_message(ERROR_DIR_NOT_EMPTY);
+            Assert::IsTrue(result.has_value());
+            Assert::IsFalse(result->empty());
+        }
+    };
+}

src/common/UnitTests-CommonUtils/Window.Tests.cpp

@@ -0,0 +1,159 @@
+#include "pch.h"
+#include "TestHelpers.h"
+#include <window.h>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTestsCommonUtils
+{
+    TEST_CLASS(WindowTests)
+    {
+    public:
+        // is_system_window tests
+        TEST_METHOD(IsSystemWindow_DesktopWindow_ReturnsResult)
+        {
+            HWND desktop = GetDesktopWindow();
+            Assert::IsNotNull(desktop);
+
+            // Get class name
+            char className[256] = {};
+            GetClassNameA(desktop, className, sizeof(className));
+
+            bool result = is_system_window(desktop, className);
+            // Just verify it doesn't crash and returns a boolean
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsSystemWindow_NullHwnd_ReturnsFalse)
+        {
+            auto shell = GetShellWindow();
+            auto desktop = GetDesktopWindow();
+            bool result = is_system_window(nullptr, "ClassName");
+            bool expected = (shell == nullptr) || (desktop == nullptr);
+            Assert::AreEqual(expected, result);
+        }
+
+        TEST_METHOD(IsSystemWindow_InvalidHwnd_ReturnsFalse)
+        {
+            bool result = is_system_window(reinterpret_cast<HWND>(0x12345678), "ClassName");
+            Assert::IsFalse(result);
+        }
+
+        TEST_METHOD(IsSystemWindow_EmptyClassName_DoesNotCrash)
+        {
+            HWND desktop = GetDesktopWindow();
+            bool result = is_system_window(desktop, "");
+            // Just verify it doesn't crash
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        TEST_METHOD(IsSystemWindow_NullClassName_DoesNotCrash)
+        {
+            HWND desktop = GetDesktopWindow();
+            bool result = is_system_window(desktop, nullptr);
+            // Should handle null className gracefully
+            Assert::IsTrue(result == true || result == false);
+        }
+
+        // GetWindowCreateParam tests
+        TEST_METHOD(GetWindowCreateParam_ValidLparam_ReturnsValue)
+        {
+            struct TestData
+            {
+                int value;
+            };
+
+            TestData data{ 42 };
+            CREATESTRUCT cs{};
+            cs.lpCreateParams = &data;
+
+            auto result = GetWindowCreateParam<TestData*>(reinterpret_cast<LPARAM>(&cs));
+            Assert::IsNotNull(result);
+            Assert::AreEqual(42, result->value);
+        }
+
+        // Window data storage tests
+        TEST_METHOD(WindowData_StoreAndRetrieve_Works)
+        {
+            // Create a simple message-only window for testing
+            WNDCLASSW wc = {};
+            wc.lpfnWndProc = DefWindowProcW;
+            wc.hInstance = GetModuleHandleW(nullptr);
+            wc.lpszClassName = L"TestWindowClass_DataTest";
+            RegisterClassW(&wc);
+
+            HWND hwnd = CreateWindowExW(0, L"TestWindowClass_DataTest", L"Test",
+                                        0, 0, 0, 0, 0, HWND_MESSAGE, nullptr,
+                                        GetModuleHandleW(nullptr), nullptr);
+
+            if (hwnd)
+            {
+                int value = 42;
+                int* testValue = &value;
+                StoreWindowParam(hwnd, testValue);
+
+                auto retrieved = GetWindowParam<int*>(hwnd);
+                Assert::AreEqual(testValue, retrieved);
+
+                DestroyWindow(hwnd);
+            }
+
+            UnregisterClassW(L"TestWindowClass_DataTest", GetModuleHandleW(nullptr));
+            Assert::IsTrue(true); // Window creation might fail in test environment
+        }
+
+        // run_message_loop tests
+        TEST_METHOD(RunMessageLoop_UntilIdle_Completes)
+        {
+            // Run message loop until idle with a timeout
+            // This should complete quickly since there are no messages
+            auto start = std::chrono::steady_clock::now();
+
+            run_message_loop(true, 100);
+
+            auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::chrono::steady_clock::now() - start);
+
+            // Should complete within reasonable time
+            Assert::IsTrue(elapsed.count() < 500);
+        }
+
+        TEST_METHOD(RunMessageLoop_WithTimeout_RespectsTimeout)
+        {
+            auto start = std::chrono::steady_clock::now();
+
+            run_message_loop(false, 50);
+
+            auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::chrono::steady_clock::now() - start);
+
+            // Should take at least the timeout duration
+            // Allow some tolerance for timing
+            Assert::IsTrue(elapsed.count() >= 40 && elapsed.count() < 500);
+        }
+
+        TEST_METHOD(RunMessageLoop_ZeroTimeout_CompletesImmediately)
+        {
+            auto start = std::chrono::steady_clock::now();
+
+            run_message_loop(false, 0);
+
+            auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::chrono::steady_clock::now() - start);
+
+            // Should complete very quickly
+            Assert::IsTrue(elapsed.count() < 100);
+        }
+
+        TEST_METHOD(RunMessageLoop_NoTimeout_ProcessesMessages)
+        {
+            // Post a quit message before starting the loop
+            PostQuitMessage(0);
+
+            // Should process the quit message and exit
+            run_message_loop(false, std::nullopt);
+
+            Assert::IsTrue(true);
+        }
+    };
+}

src/common/UnitTests-CommonUtils/packages.config

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="Microsoft.Windows.CppWinRT" version="2.0.240111.5" targetFramework="native" />
+</packages>

src/common/UnitTests-CommonUtils/pch.cpp

@@ -0,0 +1,5 @@
+// pch.cpp: source file corresponding to the pre-compiled header
+
+#include "pch.h"
+
+// When you are using pre-compiled headers, this source file is necessary for compilation to succeed.

src/common/UnitTests-CommonUtils/pch.h

@@ -0,0 +1,39 @@
+// pch.h: This is a precompiled header file.
+// Files listed below are compiled only once, improving build performance for future builds.
+// This also affects IntelliSense performance, including code completion and many code browsing features.
+// However, files listed here are ALL re-compiled if any one of them is updated between builds.
+// Do not add files here that you will be updating frequently as this negates the performance advantage.
+
+#ifndef PCH_H
+#define PCH_H
+
+// add headers that you want to pre-compile here
+#include <Windows.h>
+#include <winrt/base.h>
+#include <winrt/Windows.Foundation.h>
+#include <winrt/Windows.Foundation.Collections.h>
+#include <winrt/Windows.Foundation.Metadata.h>
+#include <winrt/Windows.Data.Json.h>
+
+#include <string>
+#include <vector>
+#include <optional>
+#include <functional>
+#include <thread>
+#include <atomic>
+#include <mutex>
+#include <shared_mutex>
+#include <future>
+#include <queue>
+#include <filesystem>
+#include <fstream>
+#include <chrono>
+#include <ctime>
+
+// Suppressing 26466 - Don't use static_cast downcasts - in CppUnitTest.h
+#pragma warning(push)
+#pragma warning(disable : 26466)
+#include "CppUnitTest.h"
+#pragma warning(pop)
+
+#endif //PCH_H

src/common/UnitTests-CommonUtils/resource.h

@@ -0,0 +1,13 @@
+//{{NO_DEPENDENCIES}}
+// Microsoft Visual C++ generated include file.
+// Used by UnitTests-CommonUtils.rc
+
+//////////////////////////////
+// Non-localizable
+
+#define FILE_DESCRIPTION "PowerToys UnitTests-CommonUtils"
+#define INTERNAL_NAME "UnitTests-CommonUtils"
+#define ORIGINAL_FILENAME "UnitTests-CommonUtils.dll"
+
+// Non-localizable
+//////////////////////////////

src/common/interop/Constants.cpp

@@ -251,4 +251,40 @@ namespace winrt::PowerToys::Interop::implementation
     {
         return CommonSharedConstants::CMDPAL_SHOW_EVENT;
     }
+    hstring Constants::TogglePowerDisplayEvent()
+    {
+        return CommonSharedConstants::TOGGLE_POWER_DISPLAY_EVENT;
+    }
+    hstring Constants::TerminatePowerDisplayEvent()
+    {
+        return CommonSharedConstants::TERMINATE_POWER_DISPLAY_EVENT;
+    }
+    hstring Constants::RefreshPowerDisplayMonitorsEvent()
+    {
+        return CommonSharedConstants::REFRESH_POWER_DISPLAY_MONITORS_EVENT;
+    }
+    hstring Constants::SettingsUpdatedPowerDisplayEvent()
+    {
+        return CommonSharedConstants::SETTINGS_UPDATED_POWER_DISPLAY_EVENT;
+    }
+    hstring Constants::PowerDisplaySendSettingsTelemetryEvent()
+    {
+        return CommonSharedConstants::POWER_DISPLAY_SEND_SETTINGS_TELEMETRY_EVENT;
+    }
+    hstring Constants::HotkeyUpdatedPowerDisplayEvent()
+    {
+        return CommonSharedConstants::HOTKEY_UPDATED_POWER_DISPLAY_EVENT;
+    }
+    hstring Constants::PowerDisplayToggleMessage()
+    {
+        return CommonSharedConstants::POWER_DISPLAY_TOGGLE_MESSAGE;
+    }
+    hstring Constants::PowerDisplayApplyProfileMessage()
+    {
+        return CommonSharedConstants::POWER_DISPLAY_APPLY_PROFILE_MESSAGE;
+    }
+    hstring Constants::PowerDisplayTerminateAppMessage()
+    {
+        return CommonSharedConstants::POWER_DISPLAY_TERMINATE_APP_MESSAGE;
+    }
 }

src/common/interop/Constants.h

@@ -66,6 +66,15 @@ namespace winrt::PowerToys::Interop::implementation
         static hstring WorkspacesHotkeyEvent();
         static hstring PowerToysRunnerTerminateSettingsEvent();
         static hstring ShowCmdPalEvent();
+        static hstring TogglePowerDisplayEvent();
+        static hstring TerminatePowerDisplayEvent();
+        static hstring RefreshPowerDisplayMonitorsEvent();
+        static hstring SettingsUpdatedPowerDisplayEvent();
+        static hstring PowerDisplaySendSettingsTelemetryEvent();
+        static hstring HotkeyUpdatedPowerDisplayEvent();
+        static hstring PowerDisplayToggleMessage();
+        static hstring PowerDisplayApplyProfileMessage();
+        static hstring PowerDisplayTerminateAppMessage();
     };
 }
 

src/common/interop/Constants.idl

@@ -63,6 +63,15 @@ namespace PowerToys
             static String WorkspacesHotkeyEvent();
             static String PowerToysRunnerTerminateSettingsEvent();
             static String ShowCmdPalEvent();
+            static String TogglePowerDisplayEvent();
+            static String TerminatePowerDisplayEvent();
+            static String RefreshPowerDisplayMonitorsEvent();
+            static String SettingsUpdatedPowerDisplayEvent();
+            static String PowerDisplaySendSettingsTelemetryEvent();
+            static String HotkeyUpdatedPowerDisplayEvent();
+            static String PowerDisplayToggleMessage();
+            static String PowerDisplayApplyProfileMessage();
+            static String PowerDisplayTerminateAppMessage();
         }
     }
 }

src/common/interop/shared_constants.h

@@ -153,6 +153,23 @@ namespace CommonSharedConstants
     const wchar_t ZOOMIT_SNIP_EVENT[] = L"Local\\PowerToysZoomIt-SnipEvent-2fd9c211-436d-4f17-a902-2528aaae3e30";
     const wchar_t ZOOMIT_RECORD_EVENT[] = L"Local\\PowerToysZoomIt-RecordEvent-74539344-eaad-4711-8e83-23946e424512";
 
+    // Path to the events used by PowerDisplay
+    const wchar_t TOGGLE_POWER_DISPLAY_EVENT[] = L"Local\\PowerToysPowerDisplay-ToggleEvent-5f1a9c3e-7d2b-4e8f-9a6c-3b5d7e9f1a2c";
+    const wchar_t TERMINATE_POWER_DISPLAY_EVENT[] = L"Local\\PowerToysPowerDisplay-TerminateEvent-7b9c2e1f-8a5d-4c3e-9f6b-2a1d8c5e3b7a";
+    const wchar_t REFRESH_POWER_DISPLAY_MONITORS_EVENT[] = L"Local\\PowerToysPowerDisplay-RefreshMonitorsEvent-a3f5c8e7-9d1b-4e2f-8c6a-3b5d7e9f1a2c";
+    const wchar_t SETTINGS_UPDATED_POWER_DISPLAY_EVENT[] = L"Local\\PowerToysPowerDisplay-SettingsUpdatedEvent-2e4d6f8a-1c3b-5e7f-9a1d-4c6e8f0b2d3e";
+    const wchar_t POWER_DISPLAY_SEND_SETTINGS_TELEMETRY_EVENT[] = L"Local\\PowerToysPowerDisplay-SettingsTelemetryEvent-8c4f2a1d-5e3b-7f9c-1a6d-3b8e5f2c9a7d";
+    const wchar_t HOTKEY_UPDATED_POWER_DISPLAY_EVENT[] = L"Local\\PowerToysPowerDisplay-HotkeyUpdatedEvent-9d5f3a2b-7e1c-4b8a-6f3d-2a9e5c7b1d4f";
+
+    // IPC Messages used in PowerDisplay (Named Pipe communication)
+    const wchar_t POWER_DISPLAY_TOGGLE_MESSAGE[] = L"Toggle";
+    const wchar_t POWER_DISPLAY_APPLY_PROFILE_MESSAGE[] = L"ApplyProfile";
+    const wchar_t POWER_DISPLAY_TERMINATE_APP_MESSAGE[] = L"TerminateApp";
+
+    // Path to the events used by LightSwitch to notify PowerDisplay of theme changes
+    const wchar_t LIGHT_SWITCH_LIGHT_THEME_EVENT[] = L"Local\\PowerToysLightSwitch-LightThemeEvent-50077121-2ffc-4841-9c86-ab1bd3f9baca";
+    const wchar_t LIGHT_SWITCH_DARK_THEME_EVENT[] = L"Local\\PowerToysLightSwitch-DarkThemeEvent-b3a835c0-eaa2-49b0-b8eb-f793e3df3368";
+
     // used from quick access window
     const wchar_t CMDPAL_SHOW_EVENT[] = L"Local\\PowerToysCmdPal-ShowEvent-62336fcd-8611-4023-9b30-091a6af4cc5a";
     const wchar_t CMDPAL_EXIT_EVENT[] = L"Local\\PowerToysCmdPal-ExitEvent-eb73f6be-3f22-4b36-aee3-62924ba40bfd";

src/common/logger/logger_settings.h

@@ -83,6 +83,7 @@ struct LogSettings
     inline const static std::wstring workspacesSnapshotToolLogPath = L"workspaces-snapshot-tool-log.log";
     inline const static std::string zoomItLoggerName = "zoom-it";
     inline const static std::string lightSwitchLoggerName = "light-switch";
+    inline const static std::string powerDisplayLoggerName = "powerdisplay";
     inline const static int retention = 30;
     std::wstring logLevel;
     LogSettings();