added automated App Store screenshots via iOS simulators and fastlane deliver

tool/screenshots_ios.sh runs the existing demo-login integration test on
iPhone 6.5" (iPhone 14 Plus) and iPad 13" simulators, stores the canonical PNGs
under materials/screenshots and mirrors alpha-free JPEGs to
ios/fastlane/screenshots for `fastlane upload_screenshots`.

Fixed the demo router answering timetable/custom-events with a week, which
crashed the inline iOS widget refresh after a demo login. The screenshot test
now skips the one-time Talk notification dialog and waits longer for the app
shell on cold simulators.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

test/demo/demo_marianumconnect_test.dart

@@ -8,6 +8,7 @@ import 'package:marianum_mobile/api/marianumconnect/queries/timetable_get_school
 import 'package:marianum_mobile/api/marianumconnect/queries/timetable_get_subjects/timetable_get_subjects_response.dart';
 import 'package:marianum_mobile/api/marianumconnect/queries/timetable_get_timegrid/timetable_get_timegrid_response.dart';
 import 'package:marianum_mobile/api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
+import 'package:marianum_mobile/api/mhsl/custom_timetable_event/get/get_custom_timetable_event_response.dart';
 
 /// The demo interceptor answers MarianumConnect calls with these bodies; each
 /// must round-trip through the same parser the real query uses. A shape
@@ -57,6 +58,17 @@ void main() {
       );
     });
 
+    // Eigener Case nötig: sonst greift der timetable/<type>/<id>-Fallback und
+    // liefert eine Woche statt `{events: [...]}` (iOS-Widget-Refresh crashte).
+    test('timetable/custom-events', () {
+      expect(
+        () => GetCustomTimetableEventResponse.fromJson(
+          asMap('timetable/custom-events'),
+        ),
+        returnsNormally,
+      );
+    });
+
     test('holidays → non-empty list of McHoliday', () {
       final holidays = asList('holidays').map(McHoliday.fromJson).toList();
       expect(holidays, isNotEmpty);