This PR updates the with-styled-jsx example to use the App Router. Here
are the changes that have been made:
- Renamed the `pages` folder to the `app` folder.
- Added the `layout.tsx` file as part of the App Router.
- Updated the `package.json` file.
The following actions were performed as part of this PR:
- Ran `pnpm prettier-check` with no issues found.
- Executed the `pnpm check-examples` script.
CC: @samcx
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Co-authored-by: samcx <sam@vercel.com>