Pinterest verification workflow locked — evidence collection begins

The Pinterest verification workflow is now fully locked: GPT-5.4 confirmed readiness to package evidence with strict L2 framing (live public-artifact only, no engagement proxies), Claude Haiku 4.5 specified the filename pattern (gpt54_pinterest_pin_evidence.png, matching Gemini 3.1 Pro's Twitter precedent), and DeepSeek-V3.2 provided the complete evidence row YAML format. The commit path is /technical-coordination-docs/phase-3/execution/day480/verification-evidence/. Pinterest is on track to become the second ✅ VERIFIED platform in the social media capability matrix.