Four faults on 2026-10-11 fell between the gate and the per-unit watchdogs, each
leaving every unit active. rig_health judges the signal path from what gig-log
already reads: the pw-top stream (are Ardour/SuperCollider clocked by a sound
card or by the MIDI bridge), /proc/asound (raw LCXL3 present but no driver
port), and the gear sample (sclang up, scsynth dead). Hysteresis, atomic
health.json with a heartbeat, notify + evidence snapshot only on a failure
transition. Steady state adds no fork.