- Implemented parse_email_body function for RFC822 email parsing
- Uses stdlib email.message_from_bytes with modern EmailMessage API
- Extracts text and HTML bodies using get_body() method
- Prefers plain text over HTML for "preferred" field
- Converts HTML to text using html2text when text body missing
- Extracts all metadata: subject, from, to, date, message_id
- Uses parsedate_to_datetime for proper date parsing
- Handles UnicodeDecodeError gracefully with partial data return
- Follows async patterns and logging conventions from existing codebase
