Make `--debug-build-paths` work with `src/` directory projects (#94016)
The `--debug-build-paths` option silently dropped routes in projects
that keep their `app` or `pages` directory under `src/`. When a user
passed `src/app/foo/page.tsx`, the glob matched the file but
`categorizeAndAddPath` only recognized paths starting with `app/` or
`pages/`, so nothing was added to the resolved app paths and the build
produced no user routes. Conversely, when a user passed the bare
`app/foo/page.tsx` form against a `src/app` project, glob found nothing
and emitted `did not match any files`.
`resolveBuildPaths` now detects whether `src/app` or `src/pages` exists
and prepends `src/` to bare patterns before globbing, and
`categorizeAndAddPath` strips a leading `src/` from matched files so
route keys are normalized either way. Added a `src-dir` fixture and four
tests covering explicit `src/` prefixes, bare patterns with
auto-prefixing, and glob patterns through route groups.
next.js
4023e48d - Make `--debug-build-paths` work with `src/` directory projects (#94016)
