Migrate React Native sample to Expo prebuild

[kieran-osgood-shopify]

Summary

Lockfile maintenance doing some work on the git diff here

• migrate the React Native sample to Expo 56 prebuild/dev-client
• move native bridge tests out of generated sample native directories into module-owned locations
• replace sample-only native dependencies with Expo APIs/packages
• delete committed generated sample native projects and add a unified dev rn prebuild command with --local support
• align Expo dependency versions with expo install --check where the Shopify package proxy has the recommended version available
• remove redundant direct React Native CLI/dev dependencies and legacy mocks

Validation

• dev rn prebuild android --local
• dev rn prebuild ios --local
• dev rn test android without USE_LOCAL_SDK
• dev rn test js
• dev rn lint
• pnpm exec expo install --check from platforms/react-native/sample
• pnpm dlx expo-doctor from platforms/react-native/sample was attempted; remaining failures are from expo-doctor shelling out to npm explain, which is blocked by the workspace npm wrapper/minimum dependency age enforcement under shadowenv
• git diff --check

Notes

• This intentionally stops before CI/docs follow-up work.
• Generated platforms/react-native/sample/ios and platforms/react-native/sample/android are ignored and regenerated via Expo prebuild.
• expo, expo-build-properties, and expo-font are pinned to the newest SDK 56 versions currently available through the Shopify package proxy, and are excluded from Expo dependency validation until the proxy catches up to Expo's latest recommendations.
• dev rn test ios now runs without USE_LOCAL_SDK; local validation got as far as the CocoaPods fixture xcodebuild invocation, then failed because the current simulator UUID from the environment was unavailable.

[kieran-osgood-shopify]

• Migrate React Native sample to Expo prebuild #297 👈 (View in Graphite)
• main

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