chezmoi runs scripts as the invoking user, not root. run_once_00 was
calling apt-get/pacman directly, which fails on debian with
'Permission denied' on /var/lib/apt/lists/lock and on arch with
similar pacman lock errors. Same pattern was already correct in
run_once_20. Mirror that here.
This is the bug that blocked rye on the second attempt.
chezmoi runs run_once_* scripts as the invoking user (uid != 0).
The earlier check [[ $(id -u) -ne 0 ]] && die ... killed the script
immediately when invoked via 'chezmoi apply' or 'chezmoi init --apply'
from a normal user session.
The scripts use sudo internally for package operations (pacman/apt),
so elevation happens correctly. The id -u check was wrong: it belongs
in a script that's *meant* to be invoked as root directly, not in a
chezmoi-managed script.
