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/src/PnvPanel.Api/Endpoints/ConfigEndpoints.cs

@@ -4,6 +4,7 @@ using PnvPanel.Application.Configs.Create;
 using PnvPanel.Application.Configs.Edit;
 using PnvPanel.Application.Configs.GetConfigLink;
 using PnvPanel.Application.Configs.GetMyConfigs;
+using PnvPanel.Application.Configs.GetMySubscription;
 using PnvPanel.Application.Configs.ListAvailableInbounds;
 using PnvPanel.Application.Configs.Revoke;
 using PnvPanel.Application.Configs.Rotate;
@@ -23,6 +24,7 @@ public static class ConfigEndpoints
         group.MapPost("/configs/{id:guid}/rotate", RotateConfig);
         group.MapDelete("/configs/{id:guid}", RevokeConfig);
         group.MapGet("/configs/{id:guid}/link", GetConfigLink);
+        group.MapGet("/subscription", GetMySubscription);
 
         return app;
     }
@@ -74,6 +76,16 @@ public static class ConfigEndpoints
         var subscriptionUrl = $"{request.Scheme}://{request.Host}/sub/{result.Value.SubscriptionToken}";
         return Results.Ok(new { connectionString = result.Value.ConnectionString, subscriptionUrl });
     }
+
+    private static async Task<IResult> GetMySubscription(HttpRequest request, ISender sender, CancellationToken cancellationToken)
+    {
+        var result = await sender.Send(new GetMySubscriptionQuery(), cancellationToken);
+        if (!result.IsSuccess)
+            return result.ToHttpResult();
+
+        var subscriptionUrl = $"{request.Scheme}://{request.Host}/sub/{result.Value.SubscriptionToken}";
+        return Results.Ok(new { subscriptionUrl });
+    }
 }
 
 public sealed record CreateConfigBody(Guid InboundId, string? Label, int? DeviceLimit);