- Added optional bcc parameter to EmailOptions interface
- Updated sendEmail method to support BCC recipients
- Modified notifySubscribersOfNewEntry to use single BCC email instead of individual emails
- Improved logging to show BCC recipient count
- More efficient email delivery for multiple subscribers
- Added support for multiple PDF MIME types (application/x-pdf, etc.)
- Added fallback to file extension validation (.pdf)
- Added detailed logging for debugging upload issues
- Resolves 'Only PDF files are allowed' error for valid PDFs