next.js

b31ee944 - updated with-styletron example to utilize the app router. (#73252)

updated with-styletron example to utilize the app router. (#73252) This PR updates the with-react-foundation example for using the App Router. Here are the changes that have been made: - I renamed the `pages` folder and moved it to the `app` folder. - Added the layout.tsx file as part of the App Router. - Updated the package.json file. CC: @samcx --------- Co-authored-by: samcx <sam@vercel.com>