implemented a comprehensive client-side demo mode triggered by a "demo@" username prefix, serving curated fixture data for all app modules

lib/api/demo/data/demo_marianum_message.dart

@@ -0,0 +1,24 @@
+import '../../../state/app/modules/marianum_message/bloc/marianum_message_state.dart';
+
+/// Demo fixtures for the info messages — a single friendly welcome entry so the
+/// section is populated rather than empty.
+class DemoMarianumMessage {
+  const DemoMarianumMessage._();
+
+  static MarianumMessageList list() {
+    final today = DateTime.now();
+    final date =
+        '${today.day.toString().padLeft(2, '0')}.${today.month.toString().padLeft(2, '0')}.${today.year}';
+
+    return MarianumMessageList(
+      base: 'https://marianum-fulda.de',
+      messages: [
+        MarianumMessage(
+          name: 'Willkommen in der Marianum-App',
+          date: date,
+          url: 'https://marianum-fulda.de',
+        ),
+      ],
+    );
+  }
+}