feat: move HealthKit permission to onboarding, remove HR write

- Add .health step to onboarding between frequency and ready
- HealthStep with non-blocking permission flow (Not Now skips)
- Remove requestAuthorization() from PlayerViewModel.startWorkout()
- Guard live session start with isAuthorized check
- Remove heart rate write from HealthKit authorization popup
- Remove HR sample writing from saveWorkout (now without permission)
- Add L10n keys: healthAccess, healthAccessSubtitle, allowHealthAccess, notNow
- Add EN/DE/ES/FR translations
- Track permission decisions through analytics
- Entry animation on HealthStep (fade-in + slide-up)

HealthKit permission is now asked once during onboarding,
never interrupting workouts again.

tabatago-swift/TabataGo/Services/HealthKitService.swift

@@ -19,7 +19,6 @@ actor HealthKitService {
         [
             HKWorkoutType.workoutType(),
             HKQuantityType(.activeEnergyBurned),
-            HKQuantityType(.heartRate),
         ]
     }
 
@@ -87,20 +86,6 @@ actor HealthKitService {
             try await builder.addSamples([sample])
         }
 
-        // Heart rate samples (if captured during workout)
-        if let avgHR = data.averageHeartRate {
-            let hrType = HKQuantityType(.heartRate)
-            let hrUnit = HKUnit.count().unitDivided(by: .minute())
-            let hrQuantity = HKQuantity(unit: hrUnit, doubleValue: avgHR)
-            let hrSample = HKQuantitySample(
-                type: hrType,
-                quantity: hrQuantity,
-                start: data.startedAt,
-                end: data.completedAt
-            )
-            try await builder.addSamples([hrSample])
-        }
-
         try await builder.endCollection(at: data.completedAt)
         guard let workout = try await builder.finishWorkout() else {
             throw HealthKitError.workoutSaveFailed