Added a new `/extract-swiss-qr-code` endpoint to extract and parse Swiss QR Codes from the last page of a PDF document. Implemented the `ExtractSwissQrCode` handler method, along with helper methods to map domain value objects (`SwissQrCodeData` and `AddressData`) to DTOs.
Updated `ExceptionHandlingMiddleware` to handle the new `SwissQrCodeNotFoundException` with a 404 Not Found response.
Added integration tests in `ExtractSwissQrCodeEndpointTests` to validate the endpoint's behavior for valid requests, invalid Base64 input, empty references, and empty PDFs. Introduced a helper method to load embedded PDF resources as Base64 strings for testing.
Updated `using` directives to include necessary namespaces for the new feature and exception handling.
Implemented the ValidatePDF feature end-to-end:
- Added `/api/v1/documents/validate` Minimal API endpoint.
- Introduced centralized ExceptionHandlingMiddleware.
- Configured Swagger with `AddSwaggerDocumentation` extension.
- Enabled XML comments in `DocumentOperator.API.csproj`.
- Updated DTOs with XML comments and added `FileSizeMB`.
- Added integration tests for the ValidatePDF endpoint (3 tests).
- Registered infrastructure services (e.g., `IPdfProcessor`).
- Refactored `Program.cs` to include middleware and endpoints.
- Updated PHASENPLAN.md and ROADMAP.md to reflect progress.
- Cleaned up code and made `Program` accessible for tests.
