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.IntegrationTests/TestSupport/AuthTestHelper.cs

@@ -0,0 +1,33 @@
+using System.Net.Http.Json;
+
+namespace PnvPanel.IntegrationTests.TestSupport;
+
+public static class AuthTestHelper
+{
+    public sealed record CurrentUserResponse(Guid Id, string UserName, string Role, bool IsActivated, bool TelegramLinked);
+
+    public sealed record LoginResponse(string AccessToken, DateTimeOffset ExpiresAt, CurrentUserResponse User);
+
+    public static async Task<(Guid Id, string AccessToken)> RegisterAndLoginAsync(HttpClient client, string userName, string password)
+    {
+        var registerResponse = await client.PostJsonAsync("/api/auth/register", new { userName, password });
+        registerResponse.EnsureSuccessStatusCode();
+
+        var (id, accessToken) = await LoginAsync(client, userName, password);
+        return (id, accessToken);
+    }
+
+    public static async Task<(Guid Id, string AccessToken)> LoginAsync(HttpClient client, string userName, string password)
+    {
+        var loginResponse = await client.PostJsonAsync("/api/auth/login", new { userName, password });
+        loginResponse.EnsureSuccessStatusCode();
+        var login = await loginResponse.ReadAsAsync<LoginResponse>();
+        return (login!.User.Id, login.AccessToken);
+    }
+
+    public static async Task<string> LoginAsAdminAsync(HttpClient client)
+    {
+        var (_, accessToken) = await LoginAsync(client, PnvPanelWebApplicationFactory.AdminUserName, PnvPanelWebApplicationFactory.AdminPassword);
+        return accessToken;
+    }
+}