Refactored `IPdfDigitalSignatureService` to replace `byte[]` with `Stream` for input and output, improving memory efficiency and scalability. Updated `PdfDigitalSignatureService` implementation to support stream-based operations, including signing, checking, and extracting PDFs.
Modified `SignPdfAsync` to handle multiple signatures sequentially using streams and ensured proper disposal of intermediate streams. Updated `CheckPdfSignatureAsync` and `ExtractOriginalPdfAsync` to use streams, reducing memory overhead.
Refactored `PdfSignatureController` to use streams for file handling, enabling efficient processing of large files. Introduced helper methods for stream handling and enhanced cancellation support. Improved code maintainability by consolidating common logic and reducing duplication.
Introduced `Pkcs11Options` for configuring PKCS#11 signing workflows, including properties for library path, token selection, and signing metadata. Added `PdfSignOptionsDto` to represent signing options and `PdfSignatureCheckResultDto` with related DTOs for signature validation.
Defined `PdfSignatureCertificationLevel` enum for certification levels. Added `IPdfDigitalSignatureService` interface to support signing and validating PDF signatures. These changes enable robust and extensible handling of digital signatures.
