Firefox schema 16 (Firefox 129) moved `moz_cookies.expiry` from seconds to
milliseconds — the migration is `UPDATE moz_cookies SET expiry = expiry * 1000`
— but the reader passed the value straight through as seconds, so persistent
cookies from a current Firefox were imported ~1000× too far in the future.
Older profiles still hold seconds, so the unit is decided by `PRAGMA
user_version` rather than assumed either way.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>