next.js

eba236b5 - [backport] Scope app-entry export validation to files inside the app directory (#97357)

[backport] Scope app-entry export validation to files inside the app directory (#97357) Backports [Scope app-entry export validation to files inside the app directory (#97350)](https://github.com/vercel/next.js/pull/97350) to `next-16-3`. Fixes #96859 on the 16.3 line. The regression came from #94962, which is present in `next-16-3` (16.3.1) and absent from `next-16-2`, so 16.3 is the only release branch that needs it. Clean cherry-pick with no conflicts; every touched file is byte-identical to the merged canary commit. `cargo test -p next-custom-transforms --test errors react_server_components` passes on this branch (33 fixtures). The end-to-end suite is left to CI. <!-- NEXT_JS_LLM --> Co-authored-by: Rodrigo Arias <rodrigo@arias.me>