Update engage-native docs for Expo 55 / RN 0.83

[mintlify]

Summary

Triggered by d-sports-ecosystem/d-sports-engage-native@e44e097 — initial repo push with Expo 55 SDK upgrade.

Changes in trigger repo

• Full codebase push of d-sports-engage-native with Expo 55, React Native 0.83.4, React 19.2.0, and updated dependencies

Doc pages updated

• repositories/d-sports-engage-native.mdx:
  • Updated tech stack table: Expo 54→55, React Native 0.81→0.83, React 19→19.2, added Zustand 5, MMKV 4, Reanimated 4, Sentry, and OneSignal
  • Expanded features list with daily games, widgets, settings/account management, achievement badges
  • Added explicit EXPO_PUBLIC_* environment variable list to getting started
  • Added EAS Build profiles table and build commands
  • Added OTA update commands section
  • Updated backend integration to reference specific API client files
  • Removed stale "what changed since last docs sync" section