Add Supabase Auth to RN + Expo

Apple Sign In + magic link, persistent sessions, server-side route guards.

Install

pnpm add @supabase/supabase-js @react-native-async-storage/async-storage
npx expo install expo-apple-authentication expo-web-browser

Client setup (lib/supabase.ts)

import 'react-native-url-polyfill/auto';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { createClient } from '@supabase/supabase-js';