feat(settings): add language change functionality

- Added SettingsLanguageChanged event
- Updated SettingsBloc to handle event
- Persists language setting

Author: fulleni

lib/settings/bloc/settings_bloc.dart

@@ -48,6 +48,10 @@ class SettingsBloc extends Bloc<SettingsEvent, SettingsState> {
       _onFeedTileTypeChanged,
       transformer: sequential(),
     );
+    on<SettingsLanguageChanged>(
+      _onLanguageChanged,
+      transformer: sequential(),
+    );
     // SettingsNotificationsEnabledChanged event and handler removed.
   }
 
@@ -195,4 +199,17 @@ class SettingsBloc extends Bloc<SettingsEvent, SettingsState> {
     emit(state.copyWith(userAppSettings: updatedSettings, clearError: true));
     await _persistSettings(updatedSettings, emit);
   }
+
+  Future<void> _onLanguageChanged(
+    SettingsLanguageChanged event,
+    Emitter<SettingsState> emit,
+  ) async {
+    if (state.userAppSettings == null) return;
+
+    final updatedSettings = state.userAppSettings!.copyWith(
+      language: event.languageCode,
+    );
+    emit(state.copyWith(userAppSettings: updatedSettings, clearError: true));
+    await _persistSettings(updatedSettings, emit);
+  }
 }

lib/settings/bloc/settings_event.dart

@@ -119,6 +119,20 @@ class SettingsFeedTileTypeChanged extends SettingsEvent {
   List<Object?> get props => [tileType];
 }
 
+/// {@template settings_language_changed}
+/// Event added when the user changes the application language.
+/// {@endtemplate}
+class SettingsLanguageChanged extends SettingsEvent {
+  /// {@macro settings_language_changed}
+  const SettingsLanguageChanged(this.languageCode);
+
+  /// The newly selected language code (e.g., 'en', 'ar').
+  final AppLanguage languageCode; // Use AppLanguage typedef from ht_shared
+
+  @override
+  List<Object?> get props => [languageCode];
+}
+
 // --- Notification Settings Events ---
 // SettingsNotificationsEnabledChanged event removed as UserAppSettings
 // does not currently support a general notifications enabled flag.