[Dev][Build] VS 2026 Support (#44304)

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
This PR updates the PowerToys solution to support **Visual Studio 2026
(PlatformToolset v145)**. It centralizes the build configuration,
updates the C++ language standards, and fixes an issue with a MouseJump
unit test that appears while using the VS 2026 supported build agent.

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

- [ ] Closes: #xxx
- [x] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [x] **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

**Build System & Configuration:**
- Updated `Cpp.Build.props` to use `v145` (VS 2026) as the default
`PlatformToolset`, with fall back to `v143` for VS 2022.
- Configured C++ Language Standard:
  - `stdcpplatest` for production projects.
- Removed explicit `<PlatformToolset>` definitions from individual
project files (approx. 37 modules) to inherit correctly from the central
`Cpp.Build.props`.

**Code Refactoring & Fixes:**
- Updated `DrawingHelperTests.cs` in MouseJump Unit Test to ease the
pixel difference tolerance. This became an issue after switching to the
new VS2026 build agent.
<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

- Validated successful compilation of the entire solution. Similar
updates have been made to the .NET 10 branch, but these are much cleaner
and will be merged into that branch once fully confirmed working.

---------

Co-authored-by: Kai Tao (from Dev Box) <kaitao@microsoft.com>
Co-authored-by: Gordon Lam (SH) <yeelam@microsoft.com>

installer/PowerToysSetupVNext/SilentFilesInUseBA/SilentFilesInUseBAFunctions.cpp

@@ -1,6 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-#include "precomp.h"
+#include "pch.h"
 #include "BalBaseBAFunctions.h"
 #include "BalBaseBAFunctionsProc.h"
 
@@ -18,7 +18,6 @@ public: // IBootstrapperApplication
 
         BalLog(BOOTSTRAPPER_LOG_LEVEL_STANDARD, "*** CUSTOM BA FUNCTION SYSTEM ACTIVE *** Running detect begin BA function. fCached=%d, registrationType=%d, cPackages=%u, fCancel=%d", fCached, registrationType, cPackages, *pfCancel);
 
-    LExit:
         return hr;
     }
 
@@ -37,7 +36,6 @@ public: // IBAFunctions
         // BalExitOnFailure(hr, "Change this message to represent real error handling.");
         //-------------------------------------------------------------------------------------------------
 
-    LExit:
         return hr;
     }
 
@@ -58,7 +56,7 @@ public: // IBAFunctions
         __in DWORD cFiles,
         __in_ecount_z(cFiles) LPCWSTR* rgwzFiles,
         __in int nRecommendation,
-        __in BOOTSTRAPPER_FILES_IN_USE_TYPE source,
+        __in BOOTSTRAPPER_FILES_IN_USE_TYPE /* source */,
         __inout int* pResult
         )
     {