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/ViewModels/StatusBarViewModel.cs

@@ -0,0 +1,52 @@
+using System.Collections.Specialized;
+using ClaudeDo.Ui.Services;
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace ClaudeDo.Ui.ViewModels;
+
+public partial class StatusBarViewModel : ViewModelBase
+{
+    private readonly WorkerClient _worker;
+
+    [ObservableProperty] private string _connectionStatus = "Offline";
+    [ObservableProperty] private string _activeTasksSummary = "";
+    [ObservableProperty] private string _statusMessage = "";
+
+    public StatusBarViewModel(WorkerClient worker)
+    {
+        _worker = worker;
+
+        worker.PropertyChanged += (_, e) =>
+        {
+            if (e.PropertyName == nameof(WorkerClient.IsConnected))
+            {
+                ConnectionStatus = worker.IsConnected ? "Online" : "Offline";
+            }
+        };
+
+        worker.ActiveTasks.CollectionChanged += OnActiveTasksChanged;
+        RefreshActiveSummary();
+    }
+
+    private void OnActiveTasksChanged(object? sender, NotifyCollectionChangedEventArgs e) =>
+        RefreshActiveSummary();
+
+    private void RefreshActiveSummary()
+    {
+        if (_worker.ActiveTasks.Count == 0)
+        {
+            ActiveTasksSummary = "";
+            return;
+        }
+
+        var parts = _worker.ActiveTasks
+            .Select(t => $"{t.Slot}: {Shorten(t.TaskId)}")
+            .ToList();
+        ActiveTasksSummary = string.Join("  |  ", parts);
+    }
+
+    private static string Shorten(string id) =>
+        id.Length > 8 ? id[..8] : id;
+
+    public void ShowMessage(string msg) => StatusMessage = msg;
+}