A symlinked files/ or a symlinked directory under it let module check, the merge
gate and module add read a template from outside the repository tree, and a
symlink no template names passed them while the build's packing refuses it
(review of mesh-controller#313). Every entry under files/ must now be a plain
directory or file, and templates are read through an os.Root of the module's
directory.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>