a74f9c408b
Introduce crate-level ekg module and re-export EkgLead, EkgMonitor, EkgSnapshot, and HeartElectricalState from lib. Patient now owns an optional EKG monitor that: - auto-initializes and syncs to the first Heart organ (lead count) - supports configure_ekg_leads() for custom lead sets - exposes ekg_monitor(), ekg_monitor_mut(), and ekg_snapshot() - is advanced during Patient::update() by observing heart electrical state - contributes to patient_summary() output Examples: - demo_app adds "set ekg <lead...>" command - dashboard renders Electrocardiogram section (rhythm, rate, axis, lead amplitudes) - lead parsing and human-readable labels added Organs: - export CardiacRhythmState from organs::heart - minor refactors in heart (dedupe impl placement), bladder and brain code style cleanups Tests: - extend patient_lifecycle with EKG assertions - add ekg_monitor_tracks_leads to validate lead config and snapshot No breaking changes.