style(ui): redesign TaskDetailView with editable fields, tag chips, and accent styling

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

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

@@ -8,4 +8,7 @@ public partial class TaskDetailView : UserControl
     {
         InitializeComponent();
     }
+
+    private void OnFieldLostFocus(object? sender, Avalonia.Interactivity.RoutedEventArgs e) { }
+    private void OnTagInputKeyDown(object? sender, Avalonia.Input.KeyEventArgs e) { }
 }