Expand description
Decoding and light header extraction for format=raw Gmail messages.
format=raw returns the complete RFC 2822 message, base64url-encoded.
[decode_raw_message] (promoted here from src/cli/gmail/read.rs, fixed
in commit d7b6c0a0) turns that back into real bytes; [extract_headers]
pulls a handful of headers out of those bytes without a MIME parser or a
second format=metadata network round-trip — gmail sync
(src/cli/gmail/sync/engine.rs) needs both to write a byte-exact .eml
and populate its manifest from data already in hand.