feat(ui): open list items counter on Listen, none on Workspace

New stat listItemsOpenCount: unchecked items in all lists the user sees
(own, shared directly or through a group), shown as accent counter on
Listen in the header and the mobile bottom bar. Workspace loses its
counter. Stats refresh on list events and after deleting an item.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/lists/SharedListsView.tsx

@@ -357,6 +357,7 @@ export const SharedListsView: React.FC<SharedListsViewProps> = ({ onRefreshGloba
       )
     );
     await api.deleteListItem(activeList.id, itemId);
+    onRefreshGlobal();
   };
 
   const handleClearCompleted = async () => {