- Introduce BurnPdfCommandExtensions to simplify sending BurnPdfCommand via ISender
- Enables calling `sender.BurnPdf(envelopeId, cancel)` or `sender.BurnPdf(envelopeUuid, cancel)`
- No changes to the underlying PDF burning logic in BurnPdfCommandHandler
- Removed redundant initial info log.
- Added detailed logging after job execution:
- Logs total finalized envelope count.
- Logs UUIDs of finalized envelopes when available.
- Logs success message when no envelopes were finalized.
- Added MediatR dependency to query envelopes
- Injected GdPictureOptions via IOptions
- Updated Execute method to fetch envelopes with status 'EnvelopeCompletelySigned'
- Preserved logging with job details
- Prepared loop for further processing of envelopes
