Found by /invariants: a symlink under static/ pointing outside the site root
answered 500. The guard held — os.Root refused it and no bytes escaped — but the
response confirmed the path was there, where every other miss answers 404. Same
reasoning as a hidden bundle answering 404 rather than 403 (ADR-0024).
serveStatic now stats through the rooted FS first, so a directory, a missing
file, and a refused name are one answer. That also folds the old noListing and
staticFS into one function, since "cannot serve this" was already their shared
job.
The test uses a real temp directory rather than a MapFS, because the guard under
test belongs to os.Root; verified it fails with 500 against the previous code
before keeping it.
Splitting web_test.go at the seam the package already had — resolve_test.go for
what a path means, web_test.go for what happens once it resolves — because it
crossed FILE_LOC_WARN. Same response as content.go at entry 9.
Claude Opus 5andbdeshi
c0100231a9