This commit implements a complete rebranding of the project:
- Updated all namespaces from `DocumentOperator` to `DocumentService`.
- Renamed file paths, embedded resources, and test data references.
- Updated configuration keys, logging paths, and Redis instance names.
- Revised documentation to reflect the new project name.
- Modified project and solution files to align with the new structure.
- Updated class names, DTOs, commands, queries, and handlers.
- Adjusted middleware, controllers, and API endpoints.
- Updated Swagger metadata and API titles to `DocumentService API`.
- Refactored test namespaces, resource paths, and embedded resources.
- Updated build and deployment configurations for the new name.
- Replaced all references to `DocumentOperator` in comments and literals.
These changes ensure consistency across the codebase and documentation.
- Unit tests for CheckPdfAttachmentsQueryHandler (3 tests)
- Integration tests for PdfAttachmentController (14 tests covering both multipart and JSON endpoints)
- Tests verify: attachment detection, metadata extraction, empty PDF handling, validation errors
- All tests using Stream API (mocks with It.IsAny<Stream>())
- Total: 17 new tests, all passing
