feat(ui): My Day actions, orphan-aware grouping, menu restructure

Pending UI work:
- My Day add/remove context actions on task rows (parent removal cascades to children)
- orphan-aware grouping: a child whose parent isn't in view renders as a top-level row, not an indented draft
- shell menu restructure (Worker / Repositories submenus); 'Finalize plan' action, drop 'Queue subtasks sequentially'
- notes editor refinements
- subtask-row hover tweak (Surface3, no transition)
- bump Avalonia 12.0.0 -> 12.0.4

src/ClaudeDo.Ui/Views/Islands/Detail/DescriptionStepsCard.axaml.cs

@@ -29,7 +29,9 @@ public partial class DescriptionStepsCard : UserControl
 
     private void OnSubtaskEditLostFocus(object? sender, RoutedEventArgs e)
     {
-        if (sender is TextBox { DataContext: SubtaskRowViewModel row })
-            row.IsEditing = false;
+        if (sender is TextBox { DataContext: SubtaskRowViewModel row }
+            && DataContext is DetailsIslandViewModel vm
+            && vm.CommitSubtaskEditCommand.CanExecute(row))
+            vm.CommitSubtaskEditCommand.Execute(row);
     }
 }