Two 0.87.4 follow-ups:
1. Cron tick: existing shutdown-on-cancel test now also asserts the
advisory lock is re-acquirable after cancel-during-tick. Without
this, a refactor moving `pg_advisory_unlock` under the cancel arm
would ship green and break multi-replica safety.
2. Analysis worker: cancel-mid-dispatch left the dashboard banner stuck
on the cancelled page until a later page overwrote it. Add a
`Cancelled` AnalysisEvent variant, publish on the cancel-release
branch, wire the analysis and admin overview dashboards to clear
on it. Per-page chip rolls back from `analyzing` to `queued`.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>