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/Directory.Packages.props

@@ -24,6 +24,17 @@
     <PackageVersion Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.9" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.9" />
     <PackageVersion Include="System.IdentityModel.Tokens.Jwt" Version="8.19.1" />
+    <PackageVersion Include="Telegram.Bot" Version="22.10.1" />
     <PackageVersion Include="ThreeXui.Net" Version="1.0.0" />
+    <!-- Тестирование (M8) -->
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageVersion Include="xunit" Version="2.9.3" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.4" />
+    <PackageVersion Include="NSubstitute" Version="5.3.0" />
+    <PackageVersion Include="Microsoft.AspNetCore.Mvc.Testing" Version="10.0.9" />
+    <PackageVersion Include="Testcontainers.PostgreSql" Version="4.2.0" />
+    <!-- InMemory, не Sqlite/Npgsql — модель использует Postgres-специфичные типы (uuid[], jsonb),
+         не имеющие реляционных аналогов; InMemory игнорирует HasColumnType и не требует их маппинга. -->
+    <PackageVersion Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.9" />
   </ItemGroup>
 </Project>