feat(ui): move list-settings access from lists pane to tasks header

The gear button on list rows became noisy and overlapped with row
selection. Moves it into the tasks island header where it targets the
currently selected list. Lists pane regains a cleaner row layout.
Also: swallow GetListConfig errors on fresh lists that have no row yet.

src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs

@@ -351,8 +351,10 @@ public sealed partial class TasksIslandViewModel : ViewModelBase
     [RelayCommand]
     private void Sort() { /* placeholder — UI-only */ }
 
+    public event EventHandler? OpenListSettingsRequested;
+
     [RelayCommand]
-    private void More() { /* placeholder — UI-only */ }
+    private void OpenListSettings() => OpenListSettingsRequested?.Invoke(this, EventArgs.Empty);
 
     partial void OnSelectedTaskChanged(TaskRowViewModel? value)
     {