Implement rate limiting and enhance authentication flow

- Added rate limiting configuration for authentication endpoints, allowing customizable request limits via environment variables.
- Updated authentication flow to utilize HttpRequest for cookie management, ensuring secure handling of refresh tokens.
- Introduced a new endpoint to retrieve user subscription details.
- Enhanced the handling of Telegram bot token validation to prevent errors with empty tokens.
- Updated the application to serialize enums as strings for better documentation and compatibility with TypeScript.
- Improved test coverage for new features and adjustments in command handlers.

backend/tests/PnvPanel.Application.Tests/Admin/Nodes/RegisterNodeCommandHandlerTests.cs

@@ -11,6 +11,7 @@ public class RegisterNodeCommandHandlerTests
 {
     private readonly IXuiPanelGateway _gateway = Substitute.For<IXuiPanelGateway>();
     private readonly ISecretProtector _secretProtector = Substitute.For<ISecretProtector>();
+    private readonly ICurrentUser _currentUser = Substitute.For<ICurrentUser>();
 
     [Fact]
     public async Task Handle_WithValidAddress_RegistersNodeWithProtectedPassword()
@@ -20,7 +21,7 @@ public class RegisterNodeCommandHandlerTests
         _gateway.ValidateBaseAddress(Arg.Any<Uri>()).Returns(Result.Success());
         _secretProtector.Protect("secret-password").Returns("protected-secret-password");
 
-        var handler = new RegisterNodeCommandHandler(dbContext, _gateway, _secretProtector);
+        var handler = new RegisterNodeCommandHandler(dbContext, _gateway, _secretProtector, _currentUser);
 
         var command = new RegisterNodeCommand("node-1", "https://node1.example.com", "admin", "secret-password", "eu-west");
 
@@ -38,7 +39,7 @@ public class RegisterNodeCommandHandlerTests
     {
         using var dbContext = InMemoryDbContextFactory.Create();
 
-        var handler = new RegisterNodeCommandHandler(dbContext, _gateway, _secretProtector);
+        var handler = new RegisterNodeCommandHandler(dbContext, _gateway, _secretProtector, _currentUser);
 
         var command = new RegisterNodeCommand("node-1", "not-a-uri", "admin", "secret-password", null);
 
@@ -58,7 +59,7 @@ public class RegisterNodeCommandHandlerTests
         var error = Error.Validation("Nodes.SchemeNotAllowed", "Разрешён только HTTPS.");
         _gateway.ValidateBaseAddress(Arg.Any<Uri>()).Returns(Result.Failure(error));
 
-        var handler = new RegisterNodeCommandHandler(dbContext, _gateway, _secretProtector);
+        var handler = new RegisterNodeCommandHandler(dbContext, _gateway, _secretProtector, _currentUser);
 
         var command = new RegisterNodeCommand("node-1", "http://node1.example.com", "admin", "secret-password", null);