Deleting a user cleared only Asset/Vulnerability assignments, but users.id is
referenced by four more tables — notification_logs, ai_reports, user_groups,
audit_logs — so Postgres RESTRICT blocked the delete with a 500.
Clear every FK first. Historical rows are NULLed, not deleted, so a removed
user's notifications, AI reports and — critically — AUDIT LOG entries survive
(a user deletion must not erase who-did-what). Group memberships are removed
outright. Then expire the cached relationship state so the User.audit_logs
delete-orphan cascade doesn't re-delete the rows we just detached.
vulncheck
bf945f838f