- cyradm via admin user 'cyrus' (PLAIN auth)
- Internal mailbox naming with ^ escape for . in usernames
- IMAP admin proxy via SASL authzid for cross-user operations
- .sub subscription files (not auto-updated on renm)
- Roundcube SPECIAL-USE folders, legacy ACL on domain migration
- autocreate triggers ONLY on INBOX creation
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>