- Updated DocumentController to use class-level [Authorize] and method-level role-based authorization for sender and receiver endpoints.
- Replaced ReadEnvelopeReceiverQuery with ReadDocumentQuery for sender document retrieval; simplified response logic.
- Added a new endpoint for fully authenticated receivers to fetch documents by envelope ID from user claims.
- Refactored ReadDocumentQuery and handler to always return DocumentDto, throw NotFoundException when needed, and use _repo.Query.
- Cleaned up using directives and removed legacy error handling and logging.
