Fix title bar icon missing in single-file published builds

The title bar Image used Source="ms-appx:///Assets/Square44x44Logo.scale-200.png".
That resolves fine in a normal build (Assets/ and AmiReel.pri sit next to the exe),
but a single-file self-contained publish (IncludeAllContentForSelfExtract=true)
bundles Content items into the exe in a way ms-appx:// can no longer resolve at
runtime, leaving the title bar icon blank — reproduced with the actual
publish-win-x64.ps1 output, confirmed fixed the same way.

Load the icon from a plain embedded resource instead (same mechanism already
used for ffmpeg.exe/ffprobe.exe): the PNG is embedded via
<EmbeddedResource LogicalName="AmiReel.Assets.TitleBarIcon.png">, and
MainWindow loads it at startup via GetManifestResourceStream + BitmapImage.
SetSourceAsync. This bypasses the ms-appx/MRT resource pipeline entirely, so
it behaves identically in dotnet build, dotnet run, and a single-file publish.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

AmiReel.csproj

@@ -46,6 +46,11 @@
   <ItemGroup>
     <EmbeddedResource Include="ThirdParty\ffmpeg.exe" Condition="Exists('ThirdParty\ffmpeg.exe')" LogicalName="AmiReel.Tools.ffmpeg.exe" />
     <EmbeddedResource Include="ThirdParty\ffprobe.exe" Condition="Exists('ThirdParty\ffprobe.exe')" LogicalName="AmiReel.Tools.ffprobe.exe" />
+    <!-- Loaded at runtime via GetManifestResourceStream for the title bar icon (MainWindow.xaml.cs).
+         The Assets\*.png Content items above go through the ms-appx:// / MRT resource pipeline,
+         which a single-file self-contained publish bundles into the exe in a way that ms-appx://
+         can no longer resolve at runtime — this embedded copy sidesteps that entirely. -->
+    <EmbeddedResource Include="Assets\Square44x44Logo.scale-200.png" LogicalName="AmiReel.Assets.TitleBarIcon.png" />
   </ItemGroup>
 
   <!--