Add Telegram bot integration and enhance user management features

- Introduced Telegram.Bot package for bot functionality.
- Updated user management to include Telegram linking and blocking features.
- Enhanced activation request handling with notifications via Telegram.
- Added new database entities for Telegram link tokens and login requests.
- Implemented traffic synchronization for client stats in the XuiPanelGateway.
- Updated application structure to support new test projects and improved dependency injection for Telegram services.

backend/tests/PnvPanel.Application.Tests/Activation/RequestActivationCommandHandlerTests.cs

@@ -0,0 +1,73 @@
+using NSubstitute;
+using PnvPanel.Application.Activation;
+using PnvPanel.Application.Auth;
+using PnvPanel.Application.Common.Interfaces;
+using PnvPanel.Application.Tests.TestSupport;
+using PnvPanel.Domain.Activation;
+using Xunit;
+
+namespace PnvPanel.Application.Tests.Activation;
+
+public class RequestActivationCommandHandlerTests
+{
+    private readonly IRealtimeNotifier _notifier = Substitute.For<IRealtimeNotifier>();
+    private readonly ITelegramNotifier _telegramNotifier = Substitute.For<ITelegramNotifier>();
+    private readonly ICurrentUser _currentUser = Substitute.For<ICurrentUser>();
+
+    [Fact]
+    public async Task Handle_WhenNoPendingRequest_CreatesRequestAndNotifies()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var userId = Guid.NewGuid();
+        _currentUser.UserId.Returns(userId);
+        _currentUser.UserName.Returns("alice");
+
+        var handler = new RequestActivationCommandHandler(dbContext, _notifier, _telegramNotifier, _currentUser);
+
+        var result = await handler.Handle(new RequestActivationCommand("Please activate"), CancellationToken.None);
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        Assert.True(result.IsSuccess);
+        Assert.Equal("Please activate", result.Value.Comment);
+        Assert.Single(dbContext.ActivationRequests);
+        await _notifier.Received(1).NotifyActivationRequestedAsync(
+            Arg.Any<Guid>(), userId, "alice", "Please activate", Arg.Any<DateTimeOffset>(), Arg.Any<CancellationToken>());
+        await _telegramNotifier.Received(1).NotifyAdminsActivationRequestedAsync(
+            Arg.Any<Guid>(), "alice", "Please activate", Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_WhenPendingRequestAlreadyExists_ReturnsConflictWithoutNotifying()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var userId = Guid.NewGuid();
+        dbContext.ActivationRequests.Add(ActivationRequest.Create(userId, null));
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        _currentUser.UserId.Returns(userId);
+        _currentUser.UserName.Returns("alice");
+
+        var handler = new RequestActivationCommandHandler(dbContext, _notifier, _telegramNotifier, _currentUser);
+
+        var result = await handler.Handle(new RequestActivationCommand(null), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(ActivationErrors.AlreadyPending, result.Error);
+        await _notifier.DidNotReceive().NotifyActivationRequestedAsync(
+            Arg.Any<Guid>(), Arg.Any<Guid>(), Arg.Any<string>(), Arg.Any<string?>(), Arg.Any<DateTimeOffset>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_WhenNotAuthenticated_ReturnsUnauthorized()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        _currentUser.UserId.Returns((Guid?)null);
+
+        var handler = new RequestActivationCommandHandler(dbContext, _notifier, _telegramNotifier, _currentUser);
+
+        var result = await handler.Handle(new RequestActivationCommand(null), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(AuthErrors.Unauthorized, result.Error);
+    }
+}