Introduced DocResultController with a GET endpoint to retrieve envelope PDF documents by sending a query via MediatR. The controller returns the PDF as a file response with an appropriate filename and content type. Added necessary using directives for MediatR, ASP.NET Core MVC, and the application query.
Introduced a new WorkerController with endpoints to start, stop, and restart the background Worker service via HTTP API. The controller uses dependency injection to locate the Worker instance and logs each operation. Also removed an unused Controllers folder reference from the project file.
