With no nix build on the hive, the boot publish of the forge token for nix has no reader. Removes the ForgeSweep node, the token file, the git credential helper and hive-c0re's forge gitconfig sections.
hive-priv applies only the path its last RealiseClosure returned for that agent. On drift the swap and create record the pins of the commit the closure was built from.
A rebuild or create downloads the closure the swarm built and applies it; with none to deploy it fails and changes nothing. hive-priv takes a store path instead of an internal/meta commit and builds nothing.
