Summary

• adds generic React Native UIKit/Fabric/worklet runtime primitives used by the NativeScript React Native Screens port
• isolates the RN Native API install from aggregate global symbols and adds callback lifetime policy for RN/worklet runtimes
• adds UIKit host lifecycle, transaction, touch/hit-test, target/action, and Fabric layout-trait support with source tests and tracking docs

Companion work

• React Native Screens fork branch pushed: DjDeveloperr/react-native-screens@nativescript (aa53b54)
• Demo harness update lives in the non-git demo workspace: scripts/stress-react-nav-comprehensive.js

Verification

• for f in packages/react-native/test/*.test.js; do node "$f" || exit 1; done
• npm run check:ffi-boundaries
• screens fork: node .yarn/releases/yarn-4.1.1.cjs test:unit (332/332)
• screens fork: node .yarn/releases/yarn-4.1.1.cjs check-types
• demo: npm run typecheck
• git diff --check in runtime and screens fork
• node --check scripts/stress-react-nav-first-tap.js
• node --check scripts/stress-react-nav-comprehensive.js
• simulator-only compact comprehensive sweeps passed on port and original dedicated sims