{"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-4t81x9t3","versions":[{"created_at":"2026-06-10T07:42:15Z","element_count":89,"note":"5軸GA polish 51->98 by M5 (autonomous)","saved_by":"mcp","sha256":"3b4ba9581d9782fcdaf6185a38dda69184f66a59b465d89fab27667fb7dd90e2","version":2}]}