fix(ui): wire details-island buttons and drop dead handlers

- Bind star button to ToggleStarCommand; wrap header and subtask
  done-check ellipses in buttons (ToggleDone / ToggleSubtaskDone).
- Wire AgentStrip copy-path button to clipboard handler.
- Remove dead Notes/PromptInput/ApproveMerge/ShowWorktreeModal code
  with no UI bindings.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/Views/Islands/DetailsIslandView.axaml.cs

@@ -30,14 +30,6 @@ public partial class DetailsIslandView : UserControl
                 await modal.ShowDialog(owner);
             };
 
-            vm.ShowWorktreeModal = async (worktreeVm) =>
-            {
-                var owner = TopLevel.GetTopLevel(this) as Window;
-                if (owner == null) return;
-                var modal = new WorktreeModalView { DataContext = worktreeVm };
-                await modal.ShowDialog(owner);
-            };
-
             vm.ShowMergeModal = async (mergeVm) =>
             {
                 var owner = TopLevel.GetTopLevel(this) as Window;
@@ -143,12 +135,6 @@ public partial class DetailsIslandView : UserControl
         return await tcs.Task;
     }
 
-    private void NotesLostFocus(object? sender, RoutedEventArgs e)
-    {
-        if (DataContext is DetailsIslandViewModel vm)
-            vm.SaveNotesCommand.Execute(null);
-    }
-
     private async void OnCopyDescriptionClick(object? sender, RoutedEventArgs e)
     {
         if (DataContext is not DetailsIslandViewModel vm) return;