implemented global user search integration for Talk chats with role-coded badges and direct chat creation logic

lib/view/pages/marianum_dates/search_marianum_dates.dart

@@ -22,7 +22,7 @@ class SearchMarianumDates extends SearchDelegate<MarianumDate?> {
   @override
   List<Widget>? buildActions(BuildContext context) => [
     if (query.isNotEmpty)
-      IconButton(onPressed: () => query = '', icon: const Icon(Icons.delete)),
+      IconButton(onPressed: () => query = '', icon: const Icon(Icons.clear)),
   ];
 
   @override