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

lib/widget/async_action_button.dart

@@ -15,7 +15,9 @@ Future<bool> runWithErrorDialog(
   } catch (e) {
     if (!context.mounted) return false;
     final message = errorBuilder != null ? errorBuilder(e) : errorToUserMessage(e);
-    InfoDialog.show(context, message);
+    final details = errorToTechnicalDetails(e);
+    final body = details != null && details != message ? '$message\n\n$details' : message;
+    InfoDialog.show(context, body, copyable: true, title: 'Fehler');
     return false;
   }
 }