Replace third-party POP3 client with a custom implementation using
native-tls for direct TLS socket communication. This change ensures
email messages are retrieved as raw bytes without encoding conversions
that could corrupt email data.
Key improvements:
- Direct byte-level message retrieval preserves original email structure
- Proper handling of POP3 byte-stuffing (doubled leading dots)
- Eliminates dependency on rust-pop3-client which performed unwanted
string conversions and line ending modifications
- Uses only native-tls for TLS connections (already a project dependency)
- Detect X-WS-* headers (e.g., X-WS-Attachment-UUID) as MIME headers
to ensure attachment headers like Content-Type and Content-Disposition
get normalized properly
- Add test case for attachment header normalization
- Bump version to 0.5.0
The normalization fixes malformed continuation lines in attachment
headers generated by Infomaniak webmail, where lines like
"name=file.pdf" are missing the required leading whitespace.
