Restores the Borg archives into a throwaway postgres inside the pod and passes
only when rows actually land — the pg_restore exit code is not proof, counted
rows are. Production is never touched; the repos are only read.
Automated rather than a documented cadence: a check nobody performs is the same
mistake as an untested backup, one level up. Runs on the 4th at 04:20, after the
nightly jobs. Verified manually before commit (synapse 31908 rows, MAS 16085,
wiki 251).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>