A single "Cardio" library entry (running-in-place figure, duration-logged)
plus a matching Cardio starter split tagged .cardio (HealthKit .mixedCardio),
so the Apple Watch records the real aerobic workout while the phone logs the
time — no per-machine cardio entries or schema changes.
Claude-Session: https://claude.ai/code/session_012qw2itfzKyEJ1HpsFt8Ex4
