feat(translations): add French language support and improve localization handling

frontend/src/features/settings/tabs/GeneralTab.tsx

@@ -4,6 +4,7 @@ import { Button, Card, Input, Loading } from '../../../components/common';
 import { useTranslation } from 'react-i18next';
 import type { GeneralSettings } from '../hooks/useSettingsState';
 import { MAX_FILES_PER_UPLOAD_LIMIT } from '../hooks/useSettingsState';
+import { SUPPORTED_LANGUAGES } from "../../../components/common/LanguageSelector.tsx";
 
 interface GeneralTabProps {
   generalSettings: GeneralSettings;
@@ -244,11 +245,9 @@ export const GeneralTab: React.FC<GeneralTabProps> = ({
               onChange={(e) => setGeneralSettings(prev => ({ ...prev, default_language: e.target.value }))}
               className="w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 rounded-lg bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100 focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-primary-500"
             >
-              <option value="en">English</option>
-              <option value="de">Deutsch</option>
-              <option value="nl">Nederlands</option>
-              <option value="pt">Português (Brasil)</option>
-              <option value="ru">Русский</option>
+              {SUPPORTED_LANGUAGES.map(lang => (
+                <option key={lang.code} value={lang.code}>{lang.name}</option>
+              ))}
             </select>
             <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1">
               {t('settings.general.defaultLanguageHelp')}