Refactor client update handling to support nullable parameters for name and expiration

- Updated the `UpdateClientAsync` method in `IXuiPanelGateway` to accept nullable parameters for `name` and `expiresAt`, allowing for more flexible client management without unintended modifications.
- Adjusted the `BlockUserCommandHandler`, `UnblockUserCommandHandler`, and other related command handlers to utilize the new nullable parameters, ensuring that client names remain unchanged during block/unblock operations and that expiration dates are managed correctly.
- Enhanced the billing and configuration handling to reflect the new logic for managing client states based on expiration rather than enabling/disabling, improving reliability in client status management.
- Updated tests to cover the new behavior and ensure proper functionality across the application.

frontend/src/shared/lib/i18n.ts

@@ -78,6 +78,8 @@ const resources = {
         location: 'Локация',
         label: 'Метка (необязательно)',
         noInboundsNotice: 'Пока нет доступных локаций для создания конфига. Обратитесь к администратору — необходимо, чтобы он добавил сервер.',
+        billingRequiredNotice: 'Оплата подписки истекла — создание новых конфигов недоступно, пока не продлите доступ.',
+        goToBilling: 'Перейти к оплате',
         created: 'Конфиг создан.',
         quotaExceeded: 'Достигнут лимит конфигов для вашей роли.',
         showLink: 'Ссылка / QR',
@@ -618,6 +620,8 @@ const resources = {
         location: 'Location',
         label: 'Label (optional)',
         noInboundsNotice: 'No locations are available for creating a config yet. Please contact the administrator — a server needs to be added.',
+        billingRequiredNotice: 'Your subscription has expired — creating new configs is unavailable until you renew.',
+        goToBilling: 'Go to payment',
         created: 'Config created.',
         quotaExceeded: 'Config quota reached for your role.',
         showLink: 'Link / QR',