Introduce a setup: prefix for one-time clone configuration (mutates the local environment, never a hook or CI step) with setup as its umbrella aggregator. Move use:git-commit-message to setup:git-commit-message as its first member, retiring use: — the undocumented prefix tracked in the backlog. Update both CONTRIBUTING.md prefix lists, the bare-command inventory, and the stale use: reference in branch.sh.