export ThemeContext

[abernier]

Use Case:

in a r3f project, i need to useContextBridge the ThemeContext so the useTheme() can be consumed into my Scene:

// app/App.tsx

'use client'

function App({children}) {
  const ContextBridge = useContextBridge(ThemeContext); // 👈🏻 I need `ThemeContext` HERE
  
  return (
    <ContextBridge>
      <Canvas>
        <Scene />
      </Canvas>
    </ContextBridge>
}

function Scene() {
  const { theme } = useTheme()
  
  return (
    <Box>
      <meshBasicMaterial color={theme === 'light' ? 'red' : 'green'} />
    </Box>
  )
}

thus this PR that just export ThemeContext