[SDK-4499] Update to use the app router

[adamjmcgrath]

See also auth0/docs#10293

[Widcket]

Should we update the dir structure of the tests?

[adamjmcgrath]

Done e2220b5

[Widcket]

With these changes, the sample app will no longer serve as an example of Next.js SDK + pages router, only with the app router, right?
Should we not showcase both, given that both are supported, and are likely being used in many real world apps due to incremental migration to the app directory?

[Widcket]

Even the Next.js documentation features them both:

[adamjmcgrath]

With these changes, the sample app will no longer serve as an example of Next.js SDK + pages router, only with the app router, right?

Correct

Should we not showcase both, given that both are supported, and are likely being used in many real world apps due to incremental migration to the app directory?

I disagree, there are many use cases not covered in this sample - including incremental migration. Adding support for pages would add too much bloat and would not represent a simple sample app. (we don't for example cover middleware in the sample either). For the swiss-army knife, cover all example - we have the example app in the repo

[Widcket]

I don't mean for the sample app to cover all use cases (it's not meant for that) but to cover login, logout, and show user profile with both routers (same use cases covered in the QS, for which this is the companion sample app).
I understand if you consider that overkill, but given the relative newness of the app dir router, and that vercel itself has adapted their docs around both routers, maybe that's something to consider.

[Widcket]

BTW, I don't think I mentioned that the sample app needs to cover all use cases 🤔 I wonder what gave you that impression.