- Introduced Page(Action<PdfPage>) method to apply design logic to every page in the document
- Simplified Background method by replacing per-page iteration with new Page overload
- Improved readability and maintainability by removing duplicate page loop logic
- Added `System.Linq` import to enable distinct and ordered page index selection
- Applied `ConcatMatrix` transformation once per page instead of per signature
- Improved performance and reduced redundant operations in `Background` method
- Introduced `Edit` extension methods for `Stream` and `byte[]` to allow
in-place PDF modifications via a `PdfDocument` action.
- Supports both .NET and .NET Framework projects.
- Ensures proper disposal of streams and PdfDocument instances.