custom login implementation, period-based timetable layout with overlap handling, enhanced error dialogs, and unified bottom sheets

lib/view/pages/timetable/custom_events/custom_event_edit_dialog.dart

@@ -115,7 +115,7 @@ class _CustomEventEditDialogState extends State<CustomEventEditDialog> {
       Navigator.of(context).pop();
     }).catchError((Object error) {
       if (!mounted) return;
-      InfoDialog.show(context, error.toString());
+      InfoDialog.show(context, error.toString(), copyable: true, title: 'Fehler');
     });
   }