[General] Fix gestures becoming unresponsive after a fast refresh

[j-piasecki]

Description

Fast refresh was able to make gestures unresponsive - Gesture Handler uses useMemo to store the handler tag, which gets invalidated on the fast refresh. Reanimated's useHandler/useEvent preserves their internal state, and the worklet event handler didn't rebuild. This caused a gesture with a new tag to use the event handler built for the previous tag, which was ignoring all incoming events.

This PR fixes this by tracking handler tag changes and rebuilding the event handler when it changes.

Supersedes #3997

Test plan

File1.tsx

import React from 'react';
import { View } from 'react-native';
import { GestureDetector, useTapGesture } from 'react-native-gesture-handler';

function Test() {
  const gesture = useTapGesture({
    onActivate: () => {
      console.log('onActivate');
    },
  });

  const COMMENT_THIS = 2;

  return (
    <GestureDetector gesture={gesture}>
      <View style={{ width: 100, height: 100, backgroundColor: 'red' }} />
    </GestureDetector>
  );
}

export default Test;

File2.tsx

import React from 'react';
import { GestureHandlerRootView } from 'react-native-gesture-handler';

import Test from './File1';

function Example() {
  return (
    <GestureHandlerRootView>
      <Test />
    </GestureHandlerRootView>
  );
}

export default Example;

1. Navigate to File2
2. Verify that tap works
3. Comment COMMENT_THIS and save File1
4. Check whether the tap works

[Copilot]

Pull request overview

Fixes a Fast Refresh regression where Reanimated gesture worklet event handlers could become stale and ignore events after a regenerated handlerTag.

Changes:

• Track handlerTag changes via useRef + useEffect to detect post-refresh tag regeneration.
• Force Reanimated.useEvent to rebuild the worklet event handler when the handlerTag changes.
• Deduplicate the Reanimated event names into a shared constant.

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[Copilot]

Consider adding a unit test for this regression by mocking Reanimated.useEvent and asserting the third argument (rebuild) flips to true when handlerTag changes between renders (simulating Fast Refresh preserving refs). This would prevent future changes from reintroducing the stale-closure issue.