feat: migrate Telegram Login Widget to v23 with admin-configurable settings

- Upgrade telegram-widget.js from v22 to v23 (TelegramLoginButton + ConnectedAccounts)
- TelegramLoginButton fetches widget config from API instead of hardcoded values
- Add TelegramWidgetConfig type and API method with fallback to env defaults
- Remove botUsername prop — now sourced from backend API
- Add useEffect cleanup to prevent orphaned iframes on unmount
- Add TELEGRAM_WIDGET category to admin interface settings menu
- Add i18n translations for widget settings (ru, en, zh, fa)

src/locales/ru.json

@@ -1762,6 +1762,10 @@
         "Subscription Show Devices": "Показывать устройства",
         "Telegram Stars Enabled": "Stars включены",
         "Telegram Stars Rate Rub": "Курс Stars (₽)",
+        "Telegram Widget Size": "Размер виджета",
+        "Telegram Widget Radius": "Скругление углов",
+        "Telegram Widget Userpic": "Показывать аватар",
+        "Telegram Widget Request Access": "Запрос доступа",
         "Tribute Api Key": "API ключ",
         "Tribute Donate Link": "Ссылка доната",
         "Tribute Enabled": "Tribute включен",
@@ -2164,6 +2168,7 @@
         "PAL24": "PAL24",
         "WATA": "Wata",
         "TELEGRAM": "Telegram",
+        "TELEGRAM_WIDGET": "Telegram Login Widget",
         "SUBSCRIPTIONS_CORE": "Основные",
         "SIMPLE_SUBSCRIPTION": "Простая подписка",
         "PERIODS": "Периоды",