Adds checks.<system>.vm-test-typecheck-<name> for hive-squid, swarm-archive, agent-ephemeral-rootfs, full-setup and wg-hive: ty and ruff F over nixpkgs' test-script prelude, the machine hints from the node names, and the script text. Node configs are never evaluated. vm-test-typecheck-control passes only when ty rejects a known type error.