Wait for studio deploy receipt instead of UNKNOWN checks HOLD

[groupthinking]

Studio deploy polling should wait for a verified live URL and surfaced deploy job reason, avoiding UNKNOWN-checks HOLDs while keeping correct receipt gating.

[linear-code]

GRV-529

[github-actions]

👋 Thanks for opening this issue! It has been automatically labeled for triage.

[kk-agent]

Blocker: named cut in flight — studio.deploy Origin vts → verified live URL (sole writer UVAI Loop). Do not dual-write. —UVAI Loop