EnumeratePath treated its argument as a directory: given a file, it
listed it under an empty path and ToManifest stopped with "path cannot
be empty". It now hands its one path to EnumeratePaths, which lists a
directory's files by their paths under it and a file by its name, as
EnumerateFile does. EnumeratePath's own resolution of a directory named
through a symlink goes with it, since EnumeratePaths does the same.
Model: opus-5-5