Both triage paths in the Mass Casualty Assessment tool classified a
survivor as Deceased (Black) on "no breathing + no movement" while
completely ignoring the heartbeat signal:
- domain `TriageCalculator::calculate` → `combine_assessments(Absent, None)`
returned Deceased. That branch is in fact only reachable *because* a
heartbeat makes `has_vitals()` true (breathing+movement absent alone →
Unknown) — so every "Deceased" was a live person with a pulse.
- detection `EnsembleClassifier::determine_triage` (the path used by
`classify()`) returned Deceased on `!has_breathing && !has_movement`,
also ignoring `reading.heartbeat`.
A survivor with a detectable pulse but no sensed breathing/movement is in
respiratory arrest — the most time-critical *savable* state. Reporting them
Deceased would deprioritize a rescuable person. WiFi-CSI also cannot confirm
death (no airway-repositioning step), so a pulse must override.
Fix: in both paths, if the result would be Deceased but a heartbeat is
present, return Immediate. Total absence of breathing, movement AND heartbeat
is unchanged (domain → Unknown, ensemble → Deceased).
2 safety regression tests added. Full MAT suite: 168 + 6 + 3 passed, 0 failed
(existing test_no_vitals_is_deceased still green — no heartbeat → Deceased).
c453268002