agent-health.sh used bare node names for 'ip netns exec' but netns are
named warp-<node> since the NetVM layout; the 6189793 CDP-liveness check
always failed ('No such file or directory'), logging false CRITICALs and
kill -9'ing healthy browsers every 5 min. Use warp-$node.
fleet-alert-check.sh: new 5-min critical-condition detector (per-node CDP
liveness via warp-<node> netns). Consecutive-failure state machine:
page after 2 consecutive failures, re-page every 30 min while critical,
quiet-hours-aware (first alert always pages). Emits ALERT/RECOVERY
records to ~/.local/share/fleet-alert/outbox.jsonl for the container
fleet-alert-relay hook; best-effort box-ctl notify to healthy agents.
Session: sidechat/critical-alerting-pipeline
operator