fix: address beta feedback - gallery layout fixes, Russian locale, email logo (#249)

- Add Russian (Русский) to admin settings language dropdown
- Fix Premium layout hero using thumbnail instead of hero_url
- Hide "Uncategorized" section header in Story layout for uncategorized photos
- Add PhotoLightbox to Story layout so photo clicks open full-screen view
- Use full-res images in StoryPhotoCard instead of thumbnails
- Defer public gallery auto-login text until settings/locale are loaded
- Add validation and debug logging for email logo URL construction

Co-authored-by: Paul Nothaft <[email protected]>

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

@@ -247,6 +247,7 @@ export const GeneralTab: React.FC<GeneralTabProps> = ({
               <option value="en">English</option>
               <option value="de">Deutsch</option>
               <option value="pt">Português (Brasil)</option>
+              <option value="ru">Русский</option>
             </select>
             <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1">
               {t('settings.general.defaultLanguageHelp')}