fix: downgrade to Expo SDK 54 for Expo Go compatibility
Expo Go 54 (latest available on device) cannot run SDK 55 projects.
Rewrite package.json with canonical SDK 54 versions from expo-template-tabs:
expo ~54.0.33, expo-router ~6.0.23, react 19.1.0, react-native 0.81.5
expo-sqlite ~15.0.6, expo-document-picker ~13.1.6,
expo-file-system ~18.0.12, expo-background-fetch/task-manager ~13.1.6,
expo-notifications ~0.32.16, expo-constants ~18.0.13,
expo-linking ~8.0.11, expo-splash-screen ~31.0.13,
expo-status-bar ~3.0.9, react-native-screens ~4.16.0,
react-native-safe-area-context ~5.6.0
TypeScript compiles cleanly; npm install completes without errors.
Davide Scaini
6f5abf634d