* feat: support Route Handlers
* update dev app
* init NextAuth via Route Handler in dev app
* import as type
* fix labeler
* default secret to `NEXTAUTH_SECRET`
* handle redirects
* support advanced init in Route Handlers
* use port 3000 for docs dev
* document initialization with Route Handlers
* upgrade to latest `next`
* upgrade to 13.3.0
* remove workaround
* cleanup
