Remove legacy WPF app, flatten WinUI project to repo root, rename namespace

The repo carried two parallel UIs (WPF + WinUI) sharing Models/Services via
cross-directory Link includes. Now that WinUI is the only frontend, collapse
the structure so the WinUI project IS the repo root instead of a nested
sibling folder:

- Delete the WPF project entirely (App.xaml, MainWindow.xaml, csproj) and its
  bin/obj output
- Move AmiReel.WinUI/* up to the repo root (App, MainWindow, MainPage,
  DialogHelper, Assets, Package.appxmanifest, app.manifest, Properties,
  .github/instructions, AGENTS.md) via git mv, preserving history
- Rename AmiReel.WinUI.csproj -> AmiReel.csproj; regenerate the solution as
  AmiReel.slnx (the newer XML solution format) with a single project
- Rename namespace AmigaDB.VideoRenderer.{Models,Services} -> AmiReel.{...}
  and AmiReel_WinUI -> AmiReel across all files, including the embedded
  ffmpeg/ffprobe resource logical names in the csproj and ToolExtractor
- Models/ and Services/ no longer need the Link-based cross-directory
  <Compile Include>; they're picked up by the SDK's default globbing now
  that they live under the project directory
- Rename assets/ -> branding/ (source icon art) to avoid a case-insensitive
  collision with Assets/ (packaged tile art) once both sit at repo root
- Merge the two .gitignore files into one; track the PublishProfiles pubxml
  files instead of ignoring them (no secrets, and they keep publish
  reproducible across machines) as branding, gitignore, etc.
- Simplify publish-win-x64.ps1 (drop the -Target Wpf/WinUI switch, there's
  only one target now) and rewrite README.md to describe the single-project
  layout, build/run/publish commands, and file structure

Verified: dotnet build succeeds for both AmiReel.csproj and AmiReel.slnx, and
the built exe launches and renders identically to before the move.

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

Services/AppSettingsStore.cs

@@ -1,8 +1,8 @@
 using System.IO;
 using System.Text.Json;
-using AmigaDB.VideoRenderer.Models;
+using AmiReel.Models;
 
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 public static class AppSettingsStore
 {

Services/FfmpegLibraryProbe.cs

@@ -4,7 +4,7 @@ using System.Runtime.InteropServices;
 using System.Text;
 using System.Text.RegularExpressions;
 
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 internal sealed partial class FfmpegLibraryProbe : IDisposable
 {

Services/MediaProbe.cs

@@ -1,7 +1,7 @@
 using System.Globalization;
 using System.IO;
 
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 internal sealed class MediaProbe
 {

Services/ProcessRunner.cs

@@ -4,7 +4,7 @@ using System.Text;
 using System.Text.RegularExpressions;
 using System.IO;
 
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 public sealed partial class ProcessRunner
 {

Services/RenderPipeline.cs

@@ -1,9 +1,9 @@
 using System.Globalization;
 using System.IO;
 using System.Text;
-using AmigaDB.VideoRenderer.Models;
+using AmiReel.Models;
 
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 public sealed class RenderPipeline
 {

Services/ToolExtractor.cs

@@ -2,7 +2,7 @@ using System.IO;
 using System.Reflection;
 using System.Security.Cryptography;
 
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 public sealed record ToolPaths(string Ffmpeg, string Ffprobe);
 
@@ -52,7 +52,7 @@ public static class ToolExtractor
     private static async Task<string> ExtractOneAsync(string fileName, string destination, CancellationToken token)
     {
         Assembly assembly = Assembly.GetExecutingAssembly();
-        string resourceName = $"AmigaDB.VideoRenderer.Tools.{fileName}";
+        string resourceName = $"AmiReel.Tools.{fileName}";
         await using Stream source = assembly.GetManifestResourceStream(resourceName)
             ?? throw new InvalidOperationException(
                 $"Embedded {fileName} was not found. Add it to ThirdParty and publish the application again.");

Services/UserFacingErrors.cs

@@ -1,4 +1,4 @@
-namespace AmigaDB.VideoRenderer.Services;
+namespace AmiReel.Services;
 
 public static class UserFacingErrors
 {