The Prometheus exporter reports current readings and alarm states, but it does not show whether a value has gone stale. Overnight cooks need dashboards and alerts that can detect when telemetry stopped updating.
Acceptance criteria:
- Metrics include device telemetry age seconds when device timestamps are present.
- Metrics include channel telemetry age seconds when channel timestamps are present.
- Missing timestamps are skipped instead of emitting misleading zeroes.
- Tests cover device and channel age output.
The Prometheus exporter reports current readings and alarm states, but it does not show whether a value has gone stale. Overnight cooks need dashboards and alerts that can detect when telemetry stopped updating.
Acceptance criteria: