- Added ISender dependency to send history commands
- Refactored SendFinalEmailToCreator and SendFinalEmailToReceivers to async
- Log attachment inclusion for emails
- Use Task.WhenAll for sending to multiple receivers
- Implements IPipelineBehavior<BurnPdfCommand, byte[]> to send emails to creator and receivers.
- Logs debug information when sending emails and warnings if email sending is skipped.
- Uses Envelope's FinalEmailType to determine whether to send emails.
