feat(ui): add auto-save LostFocus handlers and tag input KeyDown

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -1,4 +1,7 @@
 using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using ClaudeDo.Ui.ViewModels;
 
 namespace ClaudeDo.Ui.Views;
 
@@ -9,6 +12,23 @@ public partial class TaskDetailView : UserControl
         InitializeComponent();
     }
 
-    private void OnFieldLostFocus(object? sender, Avalonia.Interactivity.RoutedEventArgs e) { }
-    private void OnTagInputKeyDown(object? sender, Avalonia.Input.KeyEventArgs e) { }
+    private async void OnFieldLostFocus(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is TaskDetailViewModel vm)
+            await vm.SaveAsync();
+    }
+
+    private void OnTagInputKeyDown(object? sender, KeyEventArgs e)
+    {
+        if (e.Key == Key.Enter && DataContext is TaskDetailViewModel vm)
+        {
+            vm.AddTagCommand.Execute(null);
+            e.Handled = true;
+        }
+    }
+
+    public void FocusTitle()
+    {
+        this.FindControl<TextBox>("TitleBox")?.Focus();
+    }
 }