feat: Apple Watch app + Paywall + Privacy Policy + rebranding

## Major Features
- Apple Watch companion app (6 phases complete)
  - WatchConnectivity iPhone ↔ Watch
  - HealthKit integration (HR, calories)
  - SwiftUI premium UI
  - 9 complication types
  - Always-On Display support

- Paywall screen with RevenueCat integration
- Privacy Policy screen
- App rebranding: tabatago → TabataFit
- Bundle ID: com.millianlmx.tabatafit

## Changes
- New: ios/TabataFit Watch App/ (complete Watch app)
- New: app/paywall.tsx (subscription UI)
- New: app/privacy.tsx (privacy policy)
- New: src/features/watch/ (Watch sync hooks)
- New: admin-web/ (admin dashboard)
- Updated: app.json, package.json (branding)
- Updated: profile.tsx (paywall + privacy links)
- Updated: i18n translations (EN/FR/DE/ES)
- New: app icon 1024x1024

## Watch App Files
- TabataFitWatchApp.swift (entry point)
- ContentView.swift (premium UI)
- HealthKitManager.swift (HR + calories)
- WatchSessionManager.swift (communication)
- Complications/ (WidgetKit)
- UserDefaults+Shared.swift (data sharing)

admin-web/public/window.svg

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