On a deploy tree node_modules is a symlink. .gitignore's node_modules/
matches only a directory, so git ls-files -co --exclude-standard lists
the link as an untracked file and the fixtures' cpSync throws EISDIR
on it (8 failures in pinned-copy.test.mjs). stack-copy.sh never takes
node_modules from git (it archives COPY_PATHS and runs npm ci), so the
fixtures now exclude **/node_modules from the listing. The copy code is
unchanged.