cloud-cascade-debug

Investigate why an ailang publish cascade didn't fire (or fired and silently failed) on multivac. Inspects gcloud logs across the registry validator, the Pub/Sub ailang-cascade topic, and the coordinator's task queue. Use when the user says "auto-cascade didn't work", "why didn't multivac pick this up", "check cloud logs for cascade", or "the dependents didn't get bumped".