Add native picker surfaces

[pietechsolution]

Summary

• add ready-made, customisable, and custom-layout native picker integrations
• add generated design tokens and locale strings
• expand the Expo example and public SDK documentation
• preserve the existing raw venue-map API

Validation

• 472 tests passed
• strict TypeScript check passed
• package build and package-surface checks passed
• generated design and public-copy checks passed
• React Native consumer builds compiled for iOS and Android

This is an implementation checkpoint; it does not publish a package release.