Final ClassDefault app identity resolver that reads the platform bundle/package ID using PackageInfo.
final class DefaultCrossmintAppIdentityResolver implements CrossmintAppIdentityResolver
On iOS: returns the bundle identifier (e.g. com.example.myapp).
On Android: returns the package name (e.g. com.example.myapp).This mirrors the official Crossmint RN SDK’s behavior of auto-deriving
the app ID from Expo constants.