fix: harden browser runtime guards for ads and cloning

[sdk-kr]

Summary

• guard GPT command queue initialization before any googletag push call
• replace direct structuredClone usage with a safe fallback helper
• reduce browser runtime crashes from ad boot order and missing clone support

Targeted Dantry issues

• Cannot read properties of undefined reading push
• googletag cmd push is undefined
• structuredClone is not defined

Notes

• this does not claim to fully resolve effect_update_depth_exceeded
• that loop still needs URL-level reproduction after this guard patch lands

[github-actions]

Staging 배포 완료

URL: https://dev.damoang.net
이미지: staging-2face6c
Static Release: sha-2face6c
커밋: 2face6c

변경사항을 dev.damoang.net에서 확인하세요.