feat(ui): wire avalonia desktop ui to data and worker

App: build a ServiceProvider in Program.cs (AppSettings, SqliteConnectionFactory,
all repositories, GitService, WorkerClient, all view-models), apply schema, then
hand control to Avalonia. App.OnFrameworkInitializationCompleted resolves
MainWindowViewModel from the container.

Ui:
- AppSettings POCO loaded from ~/.todo-app/ui.config.json (db path, hub url).
- WorkerClient wraps HubConnection with auto-reconnect, exposes IsConnected and
  ActiveTasks plus C# events for TaskStarted/Finished/Message/Updated and
  WorktreeUpdated; all inbound events are marshalled to the UI thread.
- ViewModels: MainWindow (lists CRUD via ListEditor dialog), TaskList (load by
  list, add/edit/delete, auto WakeQueue on agent+queued create), TaskItem
  (RunNow gated on connection + status), TaskDetail (description, result, live
  ndjson rolling buffer of 500 lines, worktree branch/diff with merge/keep/
  discard via GitService), StatusBar, ListEditor, TaskEditor.
- Views: 3-pane MainWindow (lists | tasks | detail) with GridSplitters, status
  bar, dialog windows for the editors. Status badges via StatusColorConverter.
- Markdown rendering, folder picker, delete-confirmation, settings dialog and
  scroll-to-bottom on the live log are intentionally TODO -- functional
  scaffold only.

Tests: also debounce the FIFO queue test (poll instead of Task.Delay(200)) so
the assertion isn't racy when the suite runs alongside the slower git tests.
38 tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/Views/MainWindow.axaml.cs

@@ -1,4 +1,5 @@
 using Avalonia.Controls;
+using ClaudeDo.Ui.ViewModels;
 
 namespace ClaudeDo.Ui.Views;
 
@@ -8,4 +9,11 @@ public partial class MainWindow : Window
     {
         InitializeComponent();
     }
-}
+
+    protected override async void OnOpened(EventArgs e)
+    {
+        base.OnOpened(e);
+        if (DataContext is MainWindowViewModel vm)
+            await vm.InitializeAsync();
+    }
+}