CmdPal: Add mini dev center (#43939)

## Summary of the Pull Request

This PR introduces a small ribbon to the CmdPal for app developers. The
dev ribbon is dynamically added to the main window in local (non-CI)
builds. It shows the number of logged errors and warnings, the current
build configuration (Debug or Release), and whether it’s built with AOT.

The flyout shows the latest errors and warnings and lets you quickly
access the logs.


## Pictures? Pictures!

<img width="985" height="589" alt="image"
src="https://github.com/user-attachments/assets/6528b02b-b4b4-4968-91bf-e67a29f86415"
/>


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

- [x] Closes: #43318
<!-- - [ ] 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

src/modules/cmdpal/Microsoft.CmdPal.UI/MainWindow.xaml.cs

@@ -11,6 +11,7 @@ using Microsoft.CmdPal.Core.Common.Helpers;
 using Microsoft.CmdPal.Core.Common.Services;
 using Microsoft.CmdPal.Core.ViewModels.Messages;
 using Microsoft.CmdPal.Ext.ClipboardHistory.Messages;
+using Microsoft.CmdPal.UI.Controls;
 using Microsoft.CmdPal.UI.Events;
 using Microsoft.CmdPal.UI.Helpers;
 using Microsoft.CmdPal.UI.Messages;
@@ -113,7 +114,7 @@ public sealed partial class MainWindow : WindowEx,
         ExtendsContentIntoTitleBar = true;
         AppWindow.TitleBar.PreferredHeightOption = TitleBarHeightOption.Collapsed;
         SizeChanged += WindowSizeChanged;
-        RootShellPage.Loaded += RootShellPage_Loaded;
+        RootElement.Loaded += RootElementLoaded;
 
         WM_TASKBAR_RESTART = PInvoke.RegisterWindowMessage("TaskbarCreated");
 
@@ -130,7 +131,7 @@ public sealed partial class MainWindow : WindowEx,
         App.Current.Services.GetService<SettingsModel>()!.SettingsChanged += SettingsChangedHandler;
 
         // Make sure that we update the acrylic theme when the OS theme changes
-        RootShellPage.ActualThemeChanged += (s, e) => DispatcherQueue.TryEnqueue(UpdateAcrylic);
+        RootElement.ActualThemeChanged += (s, e) => DispatcherQueue.TryEnqueue(UpdateAcrylic);
 
         // Hardcoding event name to avoid bringing in the PowerToys.interop dependency. Event name must match CMDPAL_SHOW_EVENT from shared_constants.h
         NativeEventWaiter.WaitForEventLoop("Local\\PowerToysCmdPal-ShowEvent-62336fcd-8611-4023-9b30-091a6af4cc5a", () =>
@@ -165,11 +166,18 @@ public sealed partial class MainWindow : WindowEx,
 
     private void SettingsChangedHandler(SettingsModel sender, object? args) => HotReloadSettings();
 
-    private void RootShellPage_Loaded(object sender, RoutedEventArgs e) =>
-
+    private void RootElementLoaded(object sender, RoutedEventArgs e)
+    {
         // Now that our content has loaded, we can update our draggable regions
         UpdateRegionsForCustomTitleBar();
 
+        // Add dev ribbon if enabled
+        if (!BuildInfo.IsCiBuild)
+        {
+            RootElement.Children.Add(new DevRibbon { Margin = new Thickness(-1, -1, 120, -1) });
+        }
+    }
+
     private void WindowSizeChanged(object sender, WindowSizeChangedEventArgs args) => UpdateRegionsForCustomTitleBar();
 
     private void PositionCentered()
@@ -658,28 +666,28 @@ public sealed partial class MainWindow : WindowEx,
     private void UpdateRegionsForCustomTitleBar()
     {
         // Specify the interactive regions of the title bar.
-        var scaleAdjustment = RootShellPage.XamlRoot.RasterizationScale;
+        var scaleAdjustment = RootElement.XamlRoot.RasterizationScale;
 
         // Get the rectangle around our XAML content. We're going to mark this
         // rectangle as "Passthrough", so that the normal window operations
         // (resizing, dragging) don't apply in this space.
-        var transform = RootShellPage.TransformToVisual(null);
+        var transform = RootElement.TransformToVisual(null);
 
         // Reserve 16px of space at the top for dragging.
         var topHeight = 16;
         var bounds = transform.TransformBounds(new Rect(
             0,
             topHeight,
-            RootShellPage.ActualWidth,
-            RootShellPage.ActualHeight));
+            RootElement.ActualWidth,
+            RootElement.ActualHeight));
         var contentRect = GetRect(bounds, scaleAdjustment);
         var rectArray = new RectInt32[] { contentRect };
         var nonClientInputSrc = InputNonClientPointerSource.GetForWindowId(this.AppWindow.Id);
         nonClientInputSrc.SetRegionRects(NonClientRegionKind.Passthrough, rectArray);
 
         // Add a drag-able region on top
-        var w = RootShellPage.ActualWidth;
-        _ = RootShellPage.ActualHeight;
+        var w = RootElement.ActualWidth;
+        _ = RootElement.ActualHeight;
         var dragSides = new RectInt32[]
         {
             GetRect(new Rect(0, 0, w, topHeight), scaleAdjustment), // the top, {topHeight=16} tall