- Introduced `AnnotationType.PSPDFKit` constants for consistent annotation type references.
- Updated `BurnPdfCommandHandler` to use new PSPDFKit annotation types.
- Refactored method signatures and local variables for clarity (e.g., using 'var', null-coalescing for annotation properties).
- Streamlined `using` statements and memory management in PDF burning process.
- Added placeholder methods for form fields, image, and ink annotations to centralize future implementations.