feat(launcher): Campaign LA add Avalonia desktop shell

src/AcDream.Launcher/App.axaml.cs

@@ -0,0 +1,66 @@
+using AcDream.Launcher.Core.Launching;
+using AcDream.Launcher.Core.Orchestration;
+using AcDream.Launcher.Core.Profiles;
+using AcDream.Launcher.ViewModels;
+using AcDream.Platform;
+using Avalonia;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Markup.Xaml;
+
+namespace AcDream.Launcher;
+
+public sealed partial class App : Application
+{
+    private LauncherOrchestrator? _orchestrator;
+    private LauncherWindowViewModel? _viewModel;
+
+    public override void Initialize() => AvaloniaXamlLoader.Load(this);
+
+    public override void OnFrameworkInitializationCompleted()
+    {
+        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+        {
+            ApplicationPathSet paths = ApplicationPathSet.Resolve();
+            LauncherProfileStore profiles = LauncherProfileStore.ForApplicationPaths(paths);
+            LauncherInstallRecord? install = ResolveDevelopmentInstallRecord();
+            _orchestrator = new LauncherOrchestrator(
+                profiles,
+                paths,
+                LauncherExecutableSet.FromDirectory(AppContext.BaseDirectory),
+                install);
+            _viewModel = new LauncherWindowViewModel(
+                _orchestrator,
+                new AvaloniaUiDispatcher());
+            _viewModel.Initialize();
+
+            desktop.MainWindow = new MainWindow
+            {
+                DataContext = _viewModel,
+            };
+            desktop.Exit += OnDesktopExit;
+        }
+
+        base.OnFrameworkInitializationCompleted();
+    }
+
+    private static LauncherInstallRecord? ResolveDevelopmentInstallRecord()
+    {
+        // LA9 owns persisted install discovery. LA4 accepts the existing
+        // developer environment pair at this one composition root so the
+        // launch/probe UI can be exercised before the first-run body lands.
+        string? datDirectory = Environment.GetEnvironmentVariable("ACDREAM_DAT_DIR");
+        string? preparedAssetPath = Environment.GetEnvironmentVariable("ACDREAM_PAK_PATH");
+        return !string.IsNullOrWhiteSpace(datDirectory)
+            && !string.IsNullOrWhiteSpace(preparedAssetPath)
+            ? new LauncherInstallRecord(datDirectory, preparedAssetPath)
+            : null;
+    }
+
+    private void OnDesktopExit(object? sender, ControlledApplicationLifetimeExitEventArgs e)
+    {
+        _viewModel?.Dispose();
+        _orchestrator?.Dispose();
+        _viewModel = null;
+        _orchestrator = null;
+    }
+}