{"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-12-28m6sfbw","versions":[{"created_at":"2026-06-10T23:30:05Z","element_count":54,"note":"","saved_by":"mcp","sha256":"d465e9b34e31c35a182663ef11a0748821386013bed2e551c333e762ed34c75f","version":4}]}