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.Domain.Tests/Configs/TrafficSampleTests.cs

@@ -0,0 +1,21 @@
+using PnvPanel.Domain.Configs;
+using Xunit;
+
+namespace PnvPanel.Domain.Tests.Configs;
+
+public class TrafficSampleTests
+{
+    [Fact]
+    public void Create_SetsAllFields()
+    {
+        var configId = Guid.NewGuid();
+        var timestamp = DateTimeOffset.UtcNow;
+
+        var sample = TrafficSample.Create(configId, timestamp, upBytes: 1000, downBytes: 2000);
+
+        Assert.Equal(configId, sample.ConfigId);
+        Assert.Equal(timestamp, sample.Timestamp);
+        Assert.Equal(1000, sample.UpBytes);
+        Assert.Equal(2000, sample.DownBytes);
+    }
+}