Add a heartbeat to a recurring job

A heartbeat monitors a job that already has its own clock. The job pings after successful work. Silence beyond the period and grace window becomes a missed check-in, while the /fail variant reports explicit failure.

Prerequisites

• Know the job's real maximum interval, including expected jitter.
• Choose a grace window long enough for ordinary delay and runtime.
• Decide which component securely stores the returned ping URL.

Workflow