- 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