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/AppSettings.cs

@@ -0,0 +1,30 @@
+using System.Text.Json;
+using ClaudeDo.Data;
+
+namespace ClaudeDo.Ui;
+
+public sealed class AppSettings
+{
+    public string DbPath { get; set; } = "~/.todo-app/todo.db";
+    public string SignalRUrl { get; set; } = "http://127.0.0.1:47821/hub";
+
+    private static readonly string ConfigPath = Paths.Expand("~/.todo-app/ui.config.json");
+
+    public static AppSettings Load()
+    {
+        try
+        {
+            if (File.Exists(ConfigPath))
+            {
+                var json = File.ReadAllText(ConfigPath);
+                return JsonSerializer.Deserialize<AppSettings>(json,
+                    new JsonSerializerOptions { PropertyNameCaseInsensitive = true }) ?? new();
+            }
+        }
+        catch
+        {
+            // Fall through to defaults
+        }
+        return new();
+    }
+}