feat(app): save Apple Watch heart rate per race like flight battery voltage

[Saqoosha]

What

Saves the pilot's Apple Watch heart rate into each race record, exactly like flight-battery voltage — no firmware/OSD involvement.

New watchOS companion (app/HDZapWatch/)

• WatchWorkoutManager runs an HKWorkoutSession + HKLiveWorkoutBuilder — the only supported way to get continuous ~1 Hz HR on watchOS (outside a workout the watch samples every few minutes) — and streams each bpm to the phone via WCSession.sendMessage(["hr": …, "ts": …]). The workout also keeps the watch app alive wrist-down for the whole flight, and the flight is saved as a real workout in Activity on finish.
• Race START/STOP on the phone is relayed as ["race": "start"|"stop"], so once the watch app is open the workout follows the race automatically. WatchContentView shows live bpm plus a manual Start/Stop for warm-up (HR sensor lock-on takes a few seconds) and recovery.

iOS

• WatchHeartRateManager mirrors BluetoothManager's flight-battery telemetry surface: lastHeartRateBpm / lastHeartRateReceivedAt (lockstep pair) / heartRateNotifyRevision, all mutated on the main actor.
• TimerView ingests via the same conventions as ingestFlightBatteryTelemetry: race-start baseline capture, tRace anchored to arrival time and clamped to ≥ 0, dedupe (on arrival time — steady bpm is real series data), cleared at both START and RESET sites, sorted chronologically on save.
• RaceRecord gains heartRateSamples with decodeIfPresent back-compat (old JSON loads fine; old app versions ignore the new key) and validator coverage (finite/clamped tRace, bpm 1–300, chronological).
• RaceDetailView gains a heart-rate CSV share button (t_race_s,received_at,bpm) next to the battery one; RaceRecord+HeartRate mirrors RaceRecord+FlightBattery.

Project config

• project.yml: new HDZapWatch target (watchOS 11, bundle id sh.saqoo.HDZap.watchkitapp, HealthKit entitlement, workout-processing background mode, HealthKit usage strings), embedded via dependency from the iOS target.
• CLAUDE.md documents the pipeline.

Not included (deliberately)

• No HR display on the goggle OSD, no firmware change, no BLE characteristic — per scope, save-only.
• No chart in the share card / detail view yet; data is persisted and CSV-exportable, so a chart can be added later without schema changes.

Testing needed (requires Mac + devices — couldn't be done in this environment)

1. cd app && xcodegen generate — required, the checked-in .xcodeproj predates the new target/files.
2. Build both targets in Xcode; run on iPhone + paired watch (HealthKit needs real hardware).
3. Flow: open watch app → grant Health access → START a race on the phone → watch workout auto-starts → finish race → check the saved race's heart-rate CSV from race detail.

Known constraint: sendMessage requires the counterpart app to be reachable, so the auto start relay only lands when the watch app is frontmost (or already in a workout). The watch must be paired to the phone running HDZap — i.e. this targets the solo pilot-operator case.

🤖 Generated with Claude Code

https://claude.ai/code/session_01UWHtgSAWz9zLerpAj5C9Zh

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Generated by Claude Code

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