implemented a customizable chat background system with support for patterns, solid colors, and gallery images; added a dedicated settings page with live preview and adjustable blur/dim effects, updated the image cropper to support flexible aspect ratios for wallpapers, and integrated file cleanup logic during account logout.

lib/main.dart

@@ -37,6 +37,7 @@ import 'state/app/modules/timetable/bloc/timetable_bloc.dart';
 import 'storage/settings.dart';
 import 'theming/dark_app_theme.dart';
 import 'theming/light_app_theme.dart';
+import 'utils/app_paths.dart';
 import 'view/login/login.dart';
 import 'widget/app_progress_indicator.dart';
 import 'widget/breaker/breaker.dart';
@@ -72,6 +73,9 @@ Future<void> main() async {
       );
       HydratedBloc.storage = storage;
     }),
+    Future(() async {
+      AppPaths.documentsDir = (await getApplicationDocumentsDirectory()).path;
+    }),
     AccountData().waitForPopulation(),
     ShareIntentListener.instance.initialize(),
   ];
@@ -352,6 +356,10 @@ Future<void> _wipeUserState({
     await prefs.clear();
     await HydratedBloc.storage.clear();
     await const CacheView().clear();
+    // The chat background image lives outside HydratedStorage, so clear it too
+    // (best-effort) to avoid orphaning the previous user's wallpaper.
+    final backgroundImage = File(AppPaths.chatBackgroundImage);
+    if (backgroundImage.existsSync()) backgroundImage.deleteSync();
     // Stop the periodic widget refresh job so the background isolate doesn't
     // wake up every 30 minutes only to write `loggedIn=false`. Re-registers
     // on the next successful login.