chore: port vercel/app-playground

[hi-ogawa]

Porting https://github.com/vercel/app-playground to @hiogawa/react-server

https://rsc-on-vite-vercel-app-playground.vercel.app

For now, copying only /layouts part. We can follow up other features later depending on priorities.

differences

• tsconfig paths -> package.json imports subpath or plugin
• set package "type": "module" for top level cjs configs (e.g. postcss.config.js -> postcss.config.cjs)
• next/link Link -> @hiogawa/react-server/client Link
• usePathname, useSearchParams -> @hiogawa/react-server/client useRouter
• notFound -> createError({ status: 404 })
• not-found.tsx -> error.tsx can be used to handle all errors

unsupported

• metadata
• template.tsx
• useSelectedLayoutSegment

todo

• compare perf
  • start up time?
  • build time?
  • hmr time
• deploy