Enhance configuration and logging for user management commands

- Updated `.env.example` to include new settings for trusted proxies and networks for better security with X-Forwarded headers.
- Modified `BlockUserCommandHandler` and `UnblockUserCommandHandler` to include logging for gateway update failures, ensuring better traceability of issues during user blocking/unblocking.
- Adjusted tests for command handlers to incorporate logging functionality, improving test coverage and reliability.
- Updated frontend configuration to dynamically set the server port based on environment variables.

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

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
 using PnvPanel.Application.Common.Interfaces;
 using PnvPanel.Application.Common.Messaging;
 using PnvPanel.Application.Common.Models;
@@ -10,7 +11,8 @@ namespace PnvPanel.Application.Admin.Users;
 /// <summary>Блокировка гасит все активные конфиги в 3x-ui (см. architecture.md).</summary>
 public sealed class BlockUserCommandHandler(
     IAppDbContext dbContext, IIdentityService identityService, IXuiPanelGateway gateway,
-    IRealtimeNotifier notifier, ITelegramNotifier telegramNotifier, ICurrentUser currentUser)
+    IRealtimeNotifier notifier, ITelegramNotifier telegramNotifier, ICurrentUser currentUser,
+    ILogger<BlockUserCommandHandler> logger)
     : ICommandHandler<BlockUserCommand, Result>
 {
     public async Task<Result> Handle(BlockUserCommand command, CancellationToken cancellationToken)
@@ -32,9 +34,20 @@ public sealed class BlockUserCommandHandler(
 
             if (inbound is not null && node is not null)
             {
-                await gateway.UpdateClientAsync(
+                var updateResult = await gateway.UpdateClientAsync(
                     node, inbound.RemoteInboundId, config.ClientExternalId, config.Protocol,
                     config.Label ?? config.ClientEmail, config.DeviceLimit, enable: false, cancellationToken);
+
+                if (!updateResult.IsSuccess)
+                {
+                    // Нода недоступна/сбой панели — не помечаем Disabled локально, иначе БД разойдётся
+                    // с реальным состоянием клиента в 3x-ui (пользователь решит, что VPN погашен, а он жив).
+                    // Конфиг останется Active и будет подхвачен повторным BlockUserCommand (идемпотентен).
+                    logger.LogWarning(
+                        "Не удалось отключить клиента конфига {ConfigId} на ноде {NodeId} при блокировке пользователя {UserId}: {Error}",
+                        config.Id, node.Id, command.UserId, updateResult.Error);
+                    continue;
+                }
             }
 
             config.Disable();