[examples] Add a Vite example

### Describe the feature request

I'm delighted to read that StyleX + Vite is now officially supported via PostCSS! There is no need for using one of the two unofficial plugins anymore!

Can someone add an official instruction for adding StyleX to a new, clean Vite starter project?

I mean `pnpm create vite` with the react-ts template and just give the minimal config needed.