Module metrics 

Available on crate feature notify only.

Prometheus surface for notifications (#280).

• faucet_notifications_sent_total{channel,event,outcome} — deliveries attempted; outcome ∈ ok | error.
• faucet_notifications_dropped_total{channel,reason} — events not delivered; reason ∈ coalesced | channel_error | severity_gated.
• faucet_notification_dispatch_duration_seconds{channel} — per-delivery latency.

Follows the CLI-side convention (faucet_schedule_*, faucet_serve_*, faucet_pipeline_sla_*): plain metrics macros, low-cardinality labels only (never pipeline/row/record values as labels — those stay in logs).

Functions

record_dropped

Record a dropped notification.

record_duration

Record per-delivery dispatch latency.

record_sent

Record a delivery attempt outcome.