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/src/PnvPanel.Application/Common/Interfaces/IRealtimeNotifier.cs

@@ -0,0 +1,24 @@
+using PnvPanel.Domain.Configs;
+using PnvPanel.Domain.Nodes;
+
+namespace PnvPanel.Application.Common.Interfaces;
+
+/// <summary>
+/// Пуш событий через SignalR. Реализация (SignalRRealtimeNotifier) живёт в Api (не в Infrastructure) —
+/// ей нужен IHubContext&lt;PanelHub&gt;, а Hub, будучи транспортным механизмом, определён в Api;
+/// Infrastructure не может ссылаться на Api (обратное направление зависимостей).
+/// </summary>
+public interface IRealtimeNotifier
+{
+    Task NotifyConfigTrafficUpdatedAsync(
+        Guid userId, Guid configId, long usedUpBytes, long usedDownBytes, CancellationToken cancellationToken);
+
+    Task NotifyConfigStatusChangedAsync(Guid userId, Guid configId, ConfigStatus status, CancellationToken cancellationToken);
+
+    Task NotifyNodeStatusChangedAsync(Guid nodeId, NodeStatus status, DateTimeOffset? lastSyncAt, CancellationToken cancellationToken);
+
+    Task NotifyActivationRequestedAsync(
+        Guid requestId, Guid userId, string userName, string? comment, DateTimeOffset createdAt, CancellationToken cancellationToken);
+
+    Task NotifyUserActivatedAsync(Guid userId, CancellationToken cancellationToken);
+}