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.

backend/tests/PnvPanel.Application.Tests/Admin/Billing/ConfirmPaymentRequestCommandHandlerTests.cs

@@ -167,7 +167,8 @@ public class ConfirmPaymentRequestCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                enable: true,
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Success());
@@ -192,6 +193,8 @@ public class ConfirmPaymentRequestCommandHandlerTests
         Assert.NotNull(expiredConfig.ExpiresAt);
         Assert.NotNull(activeConfig.ExpiresAt);
         Assert.Equal(expiredConfig.ExpiresAt, activeConfig.ExpiresAt);
+        // enable: null — возврат из приостановки теперь идёт через expiresAt (новый newPaidUntil),
+        // а не через переключение enable (см. IXuiPanelGateway.UpdateClientAsync).
         await _gateway
             .Received(1)
             .UpdateClientAsync(
@@ -200,7 +203,8 @@ public class ConfirmPaymentRequestCommandHandlerTests
                 "ext-1",
                 VpnProtocol.Vless,
                 Arg.Any<string>(),
-                enable: true,
+                null,
+                Arg.Is<DateTimeOffset?>(d => d == expiredConfig.ExpiresAt),
                 Arg.Any<CancellationToken>()
             );
     }

backend/tests/PnvPanel.Application.Tests/Admin/Support/ApproveExtensionRequestCommandHandlerTests.cs

@@ -128,7 +128,8 @@ public class ApproveExtensionRequestCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                enable: true,
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Success());

backend/tests/PnvPanel.Application.Tests/Admin/Users/BlockUserCommandHandlerTests.cs

@@ -54,7 +54,8 @@ public class BlockUserCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                Arg.Any<bool>(),
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             );
     }
@@ -91,7 +92,8 @@ public class BlockUserCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                Arg.Any<bool>(),
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Success());
@@ -111,6 +113,8 @@ public class BlockUserCommandHandlerTests
         Assert.True(result.IsSuccess);
         Assert.Equal(ConfigStatus.Disabled, config.Status);
 
+        // name: null — блокировка не переименовывает клиента; expiresAt: null — блокировка не трогает
+        // срок оплаты (см. IXuiPanelGateway.UpdateClientAsync).
         await _gateway
             .Received(1)
             .UpdateClientAsync(
@@ -118,8 +122,9 @@ public class BlockUserCommandHandlerTests
                 inbound.RemoteInboundId,
                 config.ClientExternalId,
                 config.Protocol,
-                "my-config",
+                null,
                 enable: false,
+                expiresAt: null,
                 Arg.Any<CancellationToken>()
             );
         await _notifier
@@ -168,7 +173,8 @@ public class BlockUserCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                Arg.Any<bool>(),
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             );
     }
@@ -205,7 +211,8 @@ public class BlockUserCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                Arg.Any<bool>(),
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Failure(Error.Failure("Xui.UpdateClientFailed", "Нода недоступна.")));

backend/tests/PnvPanel.Application.Tests/Admin/Users/UnblockUserCommandHandlerTests.cs

@@ -54,7 +54,8 @@ public class UnblockUserCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                Arg.Any<bool>(),
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Success());
@@ -81,6 +82,7 @@ public class UnblockUserCommandHandlerTests
                 config.Protocol,
                 Arg.Any<string>(),
                 true,
+                null,
                 Arg.Any<CancellationToken>()
             );
         await _notifier
@@ -155,7 +157,8 @@ public class UnblockUserCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<VpnProtocol>(),
                 Arg.Any<string>(),
-                Arg.Any<bool>(),
+                Arg.Any<bool?>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Failure(Error.Failure("Xui.UpdateClientFailed", "Нода недоступна.")));

backend/tests/PnvPanel.Application.Tests/Configs/Create/CreateVpnConfigCommandHandlerTests.cs

@@ -0,0 +1,128 @@
+using NSubstitute;
+using PnvPanel.Application.Common.Interfaces;
+using PnvPanel.Application.Common.Models;
+using PnvPanel.Application.Configs;
+using PnvPanel.Application.Configs.Create;
+using PnvPanel.Application.Tests.TestSupport;
+using PnvPanel.Domain.Inbounds;
+using PnvPanel.Infrastructure.Persistence;
+using Xunit;
+
+namespace PnvPanel.Application.Tests.Configs.Create;
+
+/// <summary>
+/// Только ветки ДО ReserveQuotaSlotAsync (billing-guard) — дальше хендлер уходит в
+/// pg_advisory_xact_lock, который InMemory-провайдер не поддерживает (см. CLAUDE.md/
+/// ConfigQuotaTests в IntegrationTests для позитивного пути и гонок).
+/// </summary>
+public class CreateVpnConfigCommandHandlerTests
+{
+    private readonly IIdentityService _identityService = Substitute.For<IIdentityService>();
+    private readonly IXuiPanelGateway _gateway = Substitute.For<IXuiPanelGateway>();
+
+    private static CurrentUserProfile Profile(
+        Guid userId,
+        Guid roleId,
+        bool billingEnabled,
+        DateTimeOffset? billingPaidUntil
+    ) =>
+        new(
+            userId,
+            "alice",
+            roleId,
+            "premium",
+            IsActivated: true,
+            IsBlocked: false,
+            MaxConfigs: 5,
+            MaxIpLimit: 3,
+            SubscriptionToken: "sub-token",
+            BillingEnabled: billingEnabled,
+            BillingPaidUntil: billingPaidUntil,
+            BillingSuspended: false
+        );
+
+    private async Task<(Inbound inbound, Guid roleId)> SeedAllowedInboundAsync(AppDbContext dbContext)
+    {
+        var roleId = Guid.NewGuid();
+        var node = Domain.Nodes.Node.Register(
+            "node-1",
+            new Uri("https://node1.example.com"),
+            new Domain.Nodes.NodeCredentials("admin", "protected"),
+            null
+        );
+        var inbound = Inbound.FromRemote(node.Id, "1", VpnProtocol.Vless, "remark", 443);
+        inbound.Publish(null, [roleId]);
+
+        dbContext.Nodes.Add(node);
+        dbContext.Inbounds.Add(inbound);
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        return (inbound, roleId);
+    }
+
+    [Fact]
+    public async Task Handle_WhenBillingEnabledAndPaidUntilExpired_ReturnsBillingRequired()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var userId = Guid.NewGuid();
+        var (inbound, roleId) = await SeedAllowedInboundAsync(dbContext);
+
+        _identityService
+            .GetProfileAsync(userId, Arg.Any<CancellationToken>())
+            .Returns(Profile(userId, roleId, billingEnabled: true, billingPaidUntil: DateTimeOffset.UtcNow.AddDays(-1)));
+
+        var handler = new CreateVpnConfigCommandHandler(
+            dbContext,
+            _identityService,
+            _gateway,
+            FakeCurrentUser.Authenticated(userId)
+        );
+
+        var result = await handler.Handle(
+            new CreateVpnConfigCommand(inbound.Id, null),
+            CancellationToken.None
+        );
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(ConfigErrors.BillingRequired, result.Error);
+        await _gateway
+            .DidNotReceive()
+            .AddClientAsync(
+                Arg.Any<Domain.Nodes.Node>(),
+                Arg.Any<string>(),
+                Arg.Any<VpnProtocol>(),
+                Arg.Any<string>(),
+                Arg.Any<string>(),
+                Arg.Any<int>(),
+                Arg.Any<DateTimeOffset?>(),
+                Arg.Any<CancellationToken>()
+            );
+    }
+
+    [Fact]
+    public async Task Handle_WhenBillingEnabledAndPaidUntilNull_ReturnsBillingRequired()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var userId = Guid.NewGuid();
+        var (inbound, roleId) = await SeedAllowedInboundAsync(dbContext);
+
+        _identityService
+            .GetProfileAsync(userId, Arg.Any<CancellationToken>())
+            .Returns(Profile(userId, roleId, billingEnabled: true, billingPaidUntil: null));
+
+        var handler = new CreateVpnConfigCommandHandler(
+            dbContext,
+            _identityService,
+            _gateway,
+            FakeCurrentUser.Authenticated(userId)
+        );
+
+        var result = await handler.Handle(
+            new CreateVpnConfigCommand(inbound.Id, null),
+            CancellationToken.None
+        );
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(ConfigErrors.BillingRequired, result.Error);
+    }
+}

backend/tests/PnvPanel.Application.Tests/Configs/Rotate/RotateVpnConfigCommandHandlerTests.cs

@@ -65,6 +65,7 @@ public class RotateVpnConfigCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<string>(),
                 Arg.Any<int>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Success("new-external-id"));
@@ -209,6 +210,7 @@ public class RotateVpnConfigCommandHandlerTests
                 Arg.Any<string>(),
                 Arg.Any<string>(),
                 Arg.Any<int>(),
+                Arg.Any<DateTimeOffset?>(),
                 Arg.Any<CancellationToken>()
             )
             .Returns(Result.Failure<string>(gatewayError));