Archiving an event with no admin_email queued an email_queue row with
recipient_email=null, violating the NOT NULL constraint. The error was
thrown inside the output.on('close') callback (detached from the caller),
becoming an unhandled rejection that crashed Node and dropped admin
sessions on bulk archive.
- Skip queueEmail when event.admin_email is null/empty (admin_email has
been nullable since migration 073).
- Wrap the close handler in try/catch so any post-archive failure logs
instead of crashing the process.