Improve vendor lead discovery output

[codexdigital-lab]

Summary

• add a scored vendor lead model with weighted dimensions for agent fit, paid value, integration ease, and distribution upside
• return ranked candidate segments with suggested product ids, pricing, affiliate bps, and next steps
• include outreach template and validation checks in the paid endpoint output
• update seed product output_schema for the richer response

Validation

• npx tsc --noEmit

MYA job 25: improve vendor-lead-discovery output