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/storage/settings.g.dart

@@ -18,6 +18,9 @@ Settings _$SettingsFromJson(Map<String, dynamic> json) => Settings(
   talkSettings: TalkSettings.fromJson(
     json['talkSettings'] as Map<String, dynamic>,
   ),
+  chatBackgroundSettings: ChatBackgroundSettings.fromJson(
+    json['chatBackgroundSettings'] as Map<String, dynamic>,
+  ),
   fileSettings: FileSettings.fromJson(
     json['fileSettings'] as Map<String, dynamic>,
   ),
@@ -44,6 +47,7 @@ Map<String, dynamic> _$SettingsToJson(Settings instance) => <String, dynamic>{
   'modulesSettings': instance.modulesSettings.toJson(),
   'timetableSettings': instance.timetableSettings.toJson(),
   'talkSettings': instance.talkSettings.toJson(),
+  'chatBackgroundSettings': instance.chatBackgroundSettings.toJson(),
   'fileSettings': instance.fileSettings.toJson(),
   'holidaysSettings': instance.holidaysSettings.toJson(),
   'fileViewSettings': instance.fileViewSettings.toJson(),