- Removed unused `EnvelopeGenerator.Domain.Entities` import.
- Changed `SendFinalEmailWithAttachment` calls to explicitly cast envelope email type to `int`.
- Removed `Debug` conditional checks around history creation; history commands are now always sent.
- Made `SendFinalEmailWithAttachment` a static method for clarity.
- 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.
