feat: implement Haptika PPG and Watch V1

src/features/ppg/health/healthKitService.ts

@@ -0,0 +1,55 @@
+import {
+  haptikaHealthKit,
+  type NativeHeartbeatSeriesSummary,
+  type NativeHealthMetricSample,
+} from 'react-native-haptika-ppg';
+
+import type {HealthKitContext, HealthMetricSample} from './healthTypes';
+
+const mapSample = (sample: NativeHealthMetricSample): HealthMetricSample => ({
+  type: sample.type,
+  value: sample.value,
+  unit: sample.unit,
+  startDate: sample.startDate,
+  endDate: sample.endDate,
+  sourceName: sample.sourceName ?? null,
+  sourceBundleIdentifier: sample.sourceBundleIdentifier ?? null,
+  deviceName: sample.deviceName ?? null,
+});
+
+export const healthKitService = {
+  isAvailable(): boolean {
+    return haptikaHealthKit.isAvailable();
+  },
+
+  requestReadAuthorization(): Promise<boolean> {
+    return haptikaHealthKit.requestReadAuthorization();
+  },
+
+  async fetchContext(lookbackDays = 14): Promise<HealthKitContext> {
+    const context = await haptikaHealthKit.fetchContext(lookbackDays);
+    return {
+      available: context.available,
+      // The native field retains its generated ABI name, but represents only
+      // HKAuthorizationRequestStatus.unnecessary — never proof of read access.
+      authorizationRequestSettled: context.authorized,
+      latestRestingHeartRate:
+        context.latestRestingHeartRate === undefined
+          ? null
+          : mapSample(context.latestRestingHeartRate),
+      latestHrvSdnn:
+        context.latestHrvSdnn === undefined
+          ? null
+          : mapSample(context.latestHrvSdnn),
+      recentHeartRateSamples: context.recentHeartRateSamples.map(mapSample),
+      contextConfidence: context.contextConfidence,
+      fetchedAt: context.fetchedAt,
+    };
+  },
+
+  fetchLatestHeartbeatSeries(): Promise<
+    NativeHeartbeatSeriesSummary | undefined
+  > {
+    return haptikaHealthKit.fetchLatestHeartbeatSeries();
+  },
+};