3rd-party/z (rupa/z) was declared but the directory doesn't exist on
disk, isn't in the git index, and nothing sources it — zoxide replaced
it as the cd-frecency tool (see rc.d/zoxide). complete-alias and
fzf-git.sh are left as-is; they still need to be initialized via the
chezmoi-managed external config that clones this repo (separate task).