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/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.")));