implemented comprehensive accessibility (A11y) support across the app

lib/view/pages/talk/chat_list.dart

@@ -85,6 +85,7 @@ class _ChatListViewState extends State<_ChatListView> {
             title: const Text('Talk'),
             actions: [
               IconButton(
+                tooltip: 'Suchen',
                 icon: const Icon(Icons.search),
                 onPressed: () {
                   final rooms = bloc.state.data?.rooms;