feat(bolt-expo): upgrade to expo sdk 57

[xKevIsDev]

Problem

bolt-expo is on Expo SDK 54, but store Expo Go (App Store and Play Store) only supports SDK 57. New Bolt Expo projects don't open on a phone until the user asks the agent to upgrade the SDK.

Solution

Upgrade the starter to SDK 57 using Expo's own tooling, and clear the Expo Doctor findings that come with it.

Implementation Details

• bolt-expo/package.json / package-lock.json - npx expo install --fix against expo@~57.0.30. This moves every expo-* package to its SDK 57 version, React to 19.2.3, React Native to 0.86.3, and the native deps (reanimated, screens, gesture-handler, svg, webview) to their SDK 57 versions. Adds react-native-worklets, which Reanimated 4 needs as a direct dependency.
• bolt-expo/app.json - removes newArchEnabled, which SDK 57's config schema no longer allows (the New Architecture is the only option now). expo install also registered the expo-splash-screen and expo-status-bar config plugins.

Verified:

• npx expo-doctor: 21/21 checks pass
• npx expo install --check: dependencies up to date
• tsc --noEmit and npm run build:web pass
• test/bolt-expo.test.ts passes in a WebContainer (web build, plus dev server with live edits)
• npm run format:check and npm run package:check pass

Not yet verified: loading the app on a physical device in Expo Go.

Expo SDK 58 shipped on 2026-10-15. Store Expo Go moves to 58 in a few weeks and will drop 57, so this will need repeating then.

Part of BOC-2463

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