Implement billing status notification and enhance user management integration

- Added `NotifyBillingStatusChangedAsync` method to `IRealtimeNotifier` for notifying clients about changes in billing status.
- Updated `BillingConfigResumer` to call the new notification method after modifying billing configurations, ensuring users receive real-time updates.
- Enhanced `ListUsersQueryHandler` to include a `BillingPendingReview` property in `UserSummaryDto`, indicating if a user has a pending payment request awaiting confirmation.
- Refactored various command handlers to utilize `AdvisoryLock` for managing concurrent requests, preventing race conditions in billing operations.
- Updated tests to cover new notification behaviors and ensure proper functionality in billing status management.

frontend/src/shared/api/types.ts

@@ -167,6 +167,9 @@ export type UserSummaryDto = {
   activatedAt: string | null
   billingEnabled: boolean
   billingPaidUntil: string | null
+  /** Есть Subscription-заявка на оплату, ожидающая решения админа — конфиги не гасятся, пока он не
+   * решит (см. BillingService). Бейдж должен показывать нейтральный статус, а не тревожный "Истекло". */
+  billingPendingReview: boolean
 }
 
 export type RoleDto = {

frontend/src/shared/lib/i18n.ts

@@ -132,6 +132,9 @@ const resources = {
         requestStatus: {
           AwaitingPayment: 'Ожидает оплаты',
           AwaitingConfirmation: 'На проверке у администратора',
+          Confirmed: 'Подтверждена',
+          Rejected: 'Отклонена',
+          Cancelled: 'Отменена',
         },
         requisites: 'Реквизиты для оплаты',
         requisitesMissing: 'Реквизиты ещё не настроены администратором.',
@@ -674,6 +677,9 @@ const resources = {
         requestStatus: {
           AwaitingPayment: 'Awaiting payment',
           AwaitingConfirmation: 'Under admin review',
+          Confirmed: 'Confirmed',
+          Rejected: 'Rejected',
+          Cancelled: 'Cancelled',
         },
         requisites: 'Payment details',
         requisitesMissing: 'The administrator has not set up payment details yet.',

frontend/src/shared/realtime/RealtimeProvider.tsx

@@ -8,6 +8,7 @@ type ConfigTrafficUpdated = { configId: string; usedUpBytes: number; usedDownByt
 type ConfigStatusChanged = { configId: string; status: ConfigStatus }
 type UserActivated = { userId: string }
 type NewsPublished = { id: string; title: string; createdAt: string }
+type BillingStatusChanged = { userId: string }
 
 /** Живые обновления по SignalR: точечно патчит кэш TanStack Query вместо инвалидации всего списка. */
 export function RealtimeProvider({ children }: { children: React.ReactNode }) {
@@ -54,10 +55,15 @@ export function RealtimeProvider({ children }: { children: React.ReactNode }) {
       void queryClient.invalidateQueries({ queryKey: ['news'] })
     }
 
+    const onBillingStatusChanged = (_payload: BillingStatusChanged) => {
+      void queryClient.invalidateQueries({ queryKey: ['my-billing-status'] })
+    }
+
     connection.on('configTrafficUpdated', onTrafficUpdated)
     connection.on('configStatusChanged', onStatusChanged)
     connection.on('userActivated', onUserActivated)
     connection.on('newsPublished', onNewsPublished)
+    connection.on('billingStatusChanged', onBillingStatusChanged)
 
     void startConnection()
 
@@ -66,6 +72,7 @@ export function RealtimeProvider({ children }: { children: React.ReactNode }) {
       connection.off('configStatusChanged', onStatusChanged)
       connection.off('userActivated', onUserActivated)
       connection.off('newsPublished', onNewsPublished)
+      connection.off('billingStatusChanged', onBillingStatusChanged)
     }
   }, [user, queryClient])