Logs and metrics

Logs

serve writes JSON lines when stdout isn't a terminal (systemd, Docker): timestamp, level, target, fields and the span context, one object per line, for Loki, Vector or jq. --log-format pretty|compact|json (or RXFERRIX_LOG_FORMAT) chooses explicitly; RUST_LOG filters as usual.

Metrics

serve --metrics [--metrics-token T] exposes Prometheus metrics at /metrics: requests by route and status, function executions and durations, commit ts and rate, sockets, subscriptions, reruns, database file sizes, scheduler queue depth, dropped log entries and, with --replicate-to and --olap, the replication and analytics lag.