Update to Caveman

{
  "name": "migration",
  "description": "Use when planning or implementing a migration that must preserve data, support rollback, and move through reversible transition steps.",
  "included_files": [
    {
      "relative_path": "agents/openai.yaml",
      "size_in_bytes": 268
    }
  ],
  "skill_md_contents": "---\nname: migration\ndescription: Use when planning or implementing a migration that must preserve data, support rollback, and move through reversible\n  transition steps.\n---\n\n# Migration\n\nMap current readers, writers, data shape, compatibility window, and ownership before editing.\n\n- Define forward path and rollback path.\n- Preserve existing data; make destructive steps explicit and separately authorized.\n- Keep mixed-version operation safe where rollout can overlap.\n- Sequence expand, migrate, verify, then contract when applicable.\n- Make retries idempotent and partial failure observable.\n- Verify old and new paths at required transition stages.\n\nStop after requested stage passes; do not perform later destructive contraction implicitly.\n"
}