fix: disable shared global context and fix reanimated hanging issue

[Kudo]

Why

fixes #208

How

• the reanimated problem was originally mentioned at [v8] Reanimated setupMicrotask UI thread worklet pollutes JS thread's global and overrides native queueMicrotask, breaking all animations software-mansion/react-native-reanimated#4953. since reanimated doesn't use the shared global context. this pr just comment out the code and unblock the reanimated integration.
• also did some refactoring to remove outdated code

Test Plan

tested on reanimated 3.15.0 with the following code

import React from 'react';
import { View, Button, StyleSheet } from 'react-native';
import Animated, {
  useSharedValue,
  useAnimatedStyle,
  withRepeat,
  withTiming,
  Easing,
  ReduceMotion,
} from 'react-native-reanimated';

const App = () => {
  const rotation = useSharedValue(0);

  const animatedStyle = useAnimatedStyle(() => {
    return {
      transform: [{ rotateZ: `${rotation.value}deg` }],
    };
  });

  const startInfiniteRotation = () => {
    rotation.value = withRepeat(
      withTiming(360, {
        duration: 2000,
        easing: Easing.linear,
        reduceMotion: ReduceMotion.Never,
      }),
      -1, // -1 for infinite repetition,
      false,
      () => {},
      ReduceMotion.Never,
    );
  };

  return (
    <View style={styles.container}>
      <Animated.View style={[styles.box, animatedStyle]} />
      <Button title="Start Rotation" onPress={startInfiniteRotation} />
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  box: {
    width: 100,
    height: 100,
    backgroundColor: 'blue',
  },
});

export default App;