feat: add localisation

lib/services/settings_service.dart

@@ -22,6 +22,10 @@ class DriftSettingsService implements SettingsService {
         (mode) => mode.name == row.themeMode,
         orElse: () => AppThemeMode.system,
       ),
+      language: AppLanguage.values.firstWhere(
+        (language) => language.name == row.language,
+        orElse: () => AppLanguage.system,
+      ),
     );
   }
 
@@ -46,6 +50,7 @@ class DriftSettingsService implements SettingsService {
             id: _settingsId,
             pinRequired: Value(settings.pinRequired),
             themeMode: Value(settings.themeMode.name),
+            language: Value(settings.language.name),
           ),
         );
   }