fix: make expo-crypto a peer dependency

[localhost41]

Summary

• move expo-crypto from runtime dependencies to peer dependencies so the host Expo app controls the native-module version
• keep SDK 56 in dev dependencies for this package’s own build and tests
• document npx expo install expo-crypto so Expo selects the version matching the app’s SDK

The peer range accepts the SDK 55 and SDK 56 module lines without forcing SDK 55 consumers onto expo-crypto@56.

Validation

• npm test -- --runInBand (485 tests)
• npm run typecheck
• npm run lint
• npm run build
• packed-package install simulation with expo-crypto@~55.0.16
• packed-package install simulation with expo-crypto@^56.0.4
• git diff --check

Closes #82

[nulllpc]

Can you quickly verify the fix against this small repo?

https://github.com/tetherto/wdk-examples/tree/main/react-native-showcase

@localhost41 Thanks a lot

[localhost41]

Verified against the current react-native-showcase using PR head bfe4f5d.

• Installed the packed PR branch into the Expo 55 showcase; expo-crypto resolves once at 55.0.18 and is shared by the app, React Native Core, and secure storage.
• WDK worklet generation completed successfully (16.6 MB bundle).
• Expo production exports completed successfully for both iOS and Android.
• Expo native autolinking resolves the same single ExpoCrypto 55.0.18 module on both platforms.

The showcase has a few unrelated existing Expo Doctor/TypeScript configuration warnings, but none are caused by this change. Looks good from my side.