- Fix RabbitMQ purge_queue to report the pre-purge message count instead of
the post-purge depth (which was always 0).
- Add shared attach_toast helper in admin templating; remove duplicated inline
_attach_toast implementations in review.py and mq.py.
- Keep purge confirmation case-sensitive so the typed safeguard works as intended.
- Fix test imports to use known-first-party 'contract_check' per isort config.
