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

lib/api/demo/data/demo_users.dart

@@ -0,0 +1,50 @@
+import '../../marianumconnect/queries/user_search/user_search_response.dart';
+
+/// Demo fixtures for the Talk user search — a small mixed set of teachers and
+/// students, filtered client-side so the demo search feels responsive.
+class DemoUsers {
+  const DemoUsers._();
+
+  static final List<McUserSearchResult> _all = [
+    McUserSearchResult(
+      username: 'm.muster',
+      firstName: 'Maria',
+      lastName: 'Mustermann',
+      userType: 'TEACHER',
+    ),
+    McUserSearchResult(
+      username: 'j.beispiel',
+      firstName: 'Jonas',
+      lastName: 'Beispiel',
+      userType: 'TEACHER',
+    ),
+    McUserSearchResult(
+      username: 'l.schueler',
+      firstName: 'Lena',
+      lastName: 'Schüler',
+      userType: 'STUDENT',
+      className: '9c',
+    ),
+    McUserSearchResult(
+      username: 'p.probe',
+      firstName: 'Paul',
+      lastName: 'Probe',
+      userType: 'STUDENT',
+      className: 'Q2',
+    ),
+  ];
+
+  static List<McUserSearchResult> search(String query) {
+    final q = query.trim().toLowerCase();
+    if (q.length < 2) return const [];
+    return _all
+        .where(
+          (u) =>
+              u.firstName.toLowerCase().contains(q) ||
+              u.lastName.toLowerCase().contains(q) ||
+              u.username.toLowerCase().contains(q) ||
+              '${u.firstName} ${u.lastName}'.toLowerCase().contains(q),
+        )
+        .toList();
+  }
+}

lib/api/demo/demo_marianumconnect.dart

@@ -1,6 +1,7 @@
 import 'data/demo_breaker.dart';
 import 'data/demo_holidays.dart';
 import 'data/demo_timetable.dart';
+import 'data/demo_users.dart';
 
 /// Single source of truth for the MarianumConnect demo responses. The demo
 /// interceptor asks this for the body of any MC request. Read endpoints reuse
@@ -32,6 +33,10 @@ class DemoMarianumConnect {
         return DemoTimetable.holidays().result.map((e) => e.toJson()).toList();
       case 'holidays':
         return DemoHolidays.upcoming().map((e) => e.toJson()).toList();
+      case 'users/search':
+        return DemoUsers.search(query['q']?.toString() ?? '')
+            .map((e) => e.toJson())
+            .toList();
       case 'breaker':
         return DemoBreaker.none().toJson();
       case 'timetable/elements/teachers':