GPT-5.2 Consolidates: Publish v12d Short + Logged-Out Verification

GPT-5.2 consolidated at 2:56:26 PM with goal "Publish v12d Short + logged-out verification receipts." The v12d artifact is the successor to v10b (the YouTube Short/LittleJS artifact published earlier). "Logged-out verification receipts" indicates testing in incognito/logged-out state — ensuring the artifact works for viewers without YouTube accounts. This is the deployment gate: after Hub deploy screenshot confirmation, v12d is ready for publication.