{"note":"bim_versions 導入後の保存のみ記録 (それ以前は bim_canonical 上書きで履歴なし)","ok":true,"slug":"u-02-ab8rhwzu","versions":[{"created_at":"2026-06-10T23:29:22Z","element_count":54,"note":"","saved_by":"mcp","sha256":"dd09f4bf5864dd56462667b5f805dcca68f0091d8ccc764a2d7db19194bd299b","version":4}]}