feat: add method to deallocate reactNativeFactory instance for iOS

[californiandreamer]

Summary

• Adds public iOS API stopReactNative() to deallocate the React Native runtime created by RCTReactNativeFactory and allow clean re‑initialization later. Fixes #134.
• Old Architecture: calls bridge.invalidate() to tear down JS and native modules.
• New Architecture: releases the runtime by dropping strong references (no public stop API on RCTHost).
• Prevents crashes when pushing a React Native screen after stopping.
• Removes stale lazy caching of rootViewFactory to avoid retaining the old runtime.
• Documentation updates for the new API and usage:
  • docs/SWIFT.md
  • docs/OBJECTIVE_C.md
• Backwards compatible: existing startReactNative() API remains; view() now self‑heals if RN was previously stopped.

Test plan

• Press the “Stop React Native” (to check app won't crash if stopReactNative called before RN was initialize)
• Push RN screen → pop → tap the “Stop React Native” button → push again (no crash).
• Repeat with both architectures toggled.
• Watch the Xcode Instruments graph to confirm RN objects are released after stop (RSS may not drop immediately).

[okwasniewski]

Thanks for working on this! 🚀

Overall looks good, left couple of questions.

[californiandreamer]

@okwasniewski, I refactored the factory a bit and added some additional checks due to Cursor Bugbot comments.

When it comes to the stopReactNative() call on the RN screen, the app is not crashing but just goes white screen. We can think about a bit better fallback. I spent some time on that and didn't find a solution yet. Will dig deeper 😄

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2025-09-24.at.22.52.53.mp4

[okwasniewski]

@californiandreamer This looks like a expected behavior if you stop react native, let's ship it.

[okwasniewski]

This is changing the previous behavior. jsLoaded should be called by React Native sending this notification

[okwasniewski]

nit: guard let reactNativeFactory else