Git branch cleanup and archival

Use to audit, archive, rename or delete branches. Verify the exact source, destination, checkout, worktrees, tip and recovery boundary first. A branch rename does not switch the active checkout. Preserve paused work and historical blockers, never delete a dirty worktree, and verify any separately authorized remote change.

Inventory actual local refs, remote refs and linked worktrees before selecting candidates. Compare ancestry, patch equivalence and available review evidence; verify unique work and dirty worktrees rather than trusting a single signal. Deletion requires applicable authorization and recoverable state; remote deletion is a separate action.

For a read-only local-branch comparison against a chosen base, run the local audit helper with Python 3 and --base <commit-or-ref>. Resolve the skill location through the current runtime's plugin interface. The helper fetches nothing, performs no deletions, snapshots branch tips and reports ancestry, patch equivalence and checked-out state as separate evidence; it fails if a comparison fails or observed refs change. Patch equivalence alone is not authorization or proof that a branch is safe to delete. Review remote and pull-request evidence separately when relevant.

To delete branches that are already integrated into the remote default branch, use the cleanup helper only with authorization for those branches. It is a two-step, plan-bound operation:

1. The default dry-run runs git fetch --prune (unless --no-fetch), classifies branches as merged (ancestor, patch-equivalent, or a merged GitHub PR into the default branch when gh works), lists the unmerged and the protected ones, and prints plan_sha256. The default branch, dev, main, master, the checked-out branch, branches checked out in a worktree and backup/* are never candidates.
2. --apply --plan-sha256 <hash> recomputes the plan from the current refs and deletes nothing if any branch tip, classification, scope or the base moved. Before deleting, it records <scope> <branch> <sha> in <git-dir>/branch-cleanup/deleted-<UTC>.tsv (restore with git branch <branch> <sha>), reads the record back and re-checks each tip.

The default scope is local. Remote branches are deleted only with an explicit --scope remote|both that was part of the reviewed dry-run, and only if they still point at the reviewed commit (git push --force-with-lease). A hash is valid only for the scope it was printed for. Run python3 test/test_git_branch_cleanup.py from the skill directory after changing the helper.

Read branch history and retirement. For linked-worktree inclusion, use content coverage. Follow the user, project and runtime authorization for each operation; this skill does not grant additional authority.