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.

backend/src/PnvPanel.Application/Admin/Users/ListUsersQueryHandler.cs

@@ -1,10 +1,12 @@
+using Microsoft.EntityFrameworkCore;
 using PnvPanel.Application.Common.Interfaces;
 using PnvPanel.Application.Common.Messaging;
 using PnvPanel.Application.Common.Models;
+using PnvPanel.Domain.Billing;
 
 namespace PnvPanel.Application.Admin.Users;
 
-public sealed class ListUsersQueryHandler(IIdentityService identityService)
+public sealed class ListUsersQueryHandler(IIdentityService identityService, IAppDbContext dbContext)
     : IQueryHandler<ListUsersQuery, Result<PagedList<UserSummaryDto>>>
 {
     public async Task<Result<PagedList<UserSummaryDto>>> Handle(
@@ -21,6 +23,29 @@ public sealed class ListUsersQueryHandler(IIdentityService identityService)
             query.Search,
             cancellationToken
         );
-        return Result.Success(result);
+
+        // IIdentityService ничего не знает про PaymentRequests (Identity не должен на них ссылаться) —
+        // подмешиваем "заявка на проверке" здесь, чтобы админский список видел ту же защиту от
+        // тревожного "Истекло", что уже показывается пользователю на /billing (PaidUntilBadge.pendingReview).
+        var userIds = result.Items.Select(u => u.Id).ToList();
+        var pendingUserIds = await dbContext
+            .PaymentRequests.Where(r =>
+                userIds.Contains(r.UserId)
+                && r.Kind == PaymentRequestKind.Subscription
+                && r.Status == PaymentRequestStatus.AwaitingConfirmation
+            )
+            .Select(r => r.UserId)
+            .ToListAsync(cancellationToken);
+        if (pendingUserIds.Count == 0)
+            return Result.Success(result);
+
+        var pendingSet = pendingUserIds.ToHashSet();
+        var enrichedItems = result
+            .Items.Select(u => pendingSet.Contains(u.Id) ? u with { BillingPendingReview = true } : u)
+            .ToList();
+
+        return Result.Success(
+            new PagedList<UserSummaryDto>(enrichedItems, result.Total, result.Page, result.PageSize)
+        );
     }
 }