{"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-20kispwj","versions":[{"created_at":"2026-06-10T18:46:38Z","element_count":52,"note":"5軸GA polish 54->92 by M5 (autonomous)","saved_by":"mcp","sha256":"563797db8438a0b863001af612e9a8974eb3d20af5a250a18f03bbf123c06f6c","version":3}]}