{"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-house-h4a415zj","versions":[{"created_at":"2026-06-10T16:55:06Z","element_count":52,"note":"5軸GA polish 60->89 by M5 (autonomous)","saved_by":"mcp","sha256":"d26cddefe367e3725eadd5d4f09bc16e36d6288d15a1062ac60ddab169a4d7b9","version":2}]}