$ca-cleanup — post-merge branch transition

Compatibility route. Prefer $ca-pr --cleanup for new usage. This installed route remains functional under the command-route compatibility policy at includes/command-compatibility.md; continue with the unchanged cleanup workflow below.

Your PR merged. You are still standing on the branch, with build output, worktree residue, and scratch files around you. This command owns the ordinary walk back: prove the branch actually landed, decide what the leftovers are, get to a clean fast-forwarded default checkout, and drop the merged local branch.

It exists because nothing else owned it. $ca-standup is daily hygiene and deliberately never touches the current branch or the default one; $ca-chore takes docs, dependency bumps, and reverts. Issue #308 recorded what the gap produced: a routine cleanup routed to $ca-chore, which refused it, and then to $ca-override — a bypass invented to cover missing coverage. This is that coverage.

Routes to

The post-merge-cleanup skill (routines/post-merge-cleanup/SKILL.md), which owns the containment proof, the artifact classification, and the per-item confirmations.

When NOT to use

• The branch has NOT merged yet → $ca-pr (finishing-a-development-branch) owns the terminal decision; come back here after it lands.
• Daily start-of-day hygiene across other branches and worktrees → $ca-standup.
• A read-only look at what is dirty → $ca-status.
• Uncommitted work you want to keep → $ca-commit. This command never commits for you.

Hard gate

• MUST prove the current branch is contained in the fetched default branch — SHA-ancestry, or a squash-merge proven by the merged PR record (headRefOid == HEAD) — before anything is deleted. An unproven or unfetched comparison STOPs — a branch that only looks merged is not merged.
• MUST classify every dirty or untracked artifact as unique, redundant, or superseded, and MUST NOT discard a unique or unclassifiable one without explicit per-item confirmation naming it.
• MUST confirm each removal individually — no batched yes, no implied yes.
• MUST reach the default branch with a clean working tree, and MUST fast-forward with --ff-only only — never a merge commit, never a rebase, never a reset that discards work.
• MUST use git branch -d, and MAY use -D only when the squash-merge PR-record proof held this run and -d refused, with that proof restated and the branch named in the confirmation. MUST NOT otherwise force-delete a branch, force-push, delete a remote branch, or write to the default branch.
• MUST NOT require $ca-override. This is ordinary lifecycle work; if it cannot proceed, the reason is a stated gate, not a bypass.