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/RejectActivationCommandHandlerTests.cs

@@ -0,0 +1,67 @@
+using NSubstitute;
+using PnvPanel.Application.Activation;
+using PnvPanel.Application.Admin.Activation;
+using PnvPanel.Application.Common.Interfaces;
+using PnvPanel.Application.Tests.TestSupport;
+using PnvPanel.Domain.Activation;
+using Xunit;
+
+namespace PnvPanel.Application.Tests.Activation;
+
+public class RejectActivationCommandHandlerTests
+{
+    private readonly ICurrentUser _currentUser = Substitute.For<ICurrentUser>();
+
+    [Fact]
+    public async Task Handle_WhenPending_RejectsWithReason()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var adminId = Guid.NewGuid();
+        var request = ActivationRequest.Create(Guid.NewGuid(), null);
+        dbContext.ActivationRequests.Add(request);
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        _currentUser.UserId.Returns(adminId);
+
+        var handler = new RejectActivationCommandHandler(dbContext, _currentUser);
+
+        var result = await handler.Handle(new RejectActivationCommand(request.Id, "недостаточно информации"), CancellationToken.None);
+
+        Assert.True(result.IsSuccess);
+        Assert.Equal(ActivationStatus.Rejected, request.Status);
+        Assert.Equal("недостаточно информации", request.RejectionReason);
+    }
+
+    [Fact]
+    public async Task Handle_WhenRequestNotFound_ReturnsNotFound()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        _currentUser.UserId.Returns(Guid.NewGuid());
+
+        var handler = new RejectActivationCommandHandler(dbContext, _currentUser);
+
+        var result = await handler.Handle(new RejectActivationCommand(Guid.NewGuid(), null), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(ActivationErrors.NotFound, result.Error);
+    }
+
+    [Fact]
+    public async Task Handle_WhenAlreadyDecided_ReturnsConflict()
+    {
+        using var dbContext = InMemoryDbContextFactory.Create();
+        var request = ActivationRequest.Create(Guid.NewGuid(), null);
+        request.Reject(Guid.NewGuid(), null);
+        dbContext.ActivationRequests.Add(request);
+        await dbContext.SaveChangesAsync(CancellationToken.None);
+
+        _currentUser.UserId.Returns(Guid.NewGuid());
+
+        var handler = new RejectActivationCommandHandler(dbContext, _currentUser);
+
+        var result = await handler.Handle(new RejectActivationCommand(request.Id, null), CancellationToken.None);
+
+        Assert.False(result.IsSuccess);
+        Assert.Equal(ActivationErrors.AlreadyDecided, result.Error);
+    }
+}