Audit log and failures

Every change is an audit entry: entity, action, who, when, before and after. The audit browser filters by entity, action, date and free text.

Failures are audit rows too. Any server error becomes a Failure entry with a short reference (like F3K7Q) that the user sees in the error message — search the reference in the audit browser and the entry names the route, the exception and the top of the stack. Quote the reference in a support ticket.