Create spec and plan to audit publsher origin headers

[aram356]

Description

1. Use superpowers skill to create a spec and plan

Example spec & plan:

Spec: https://github.com/IABTechLab/trusted-server/blob/worktree-review-ts-dev-proxy-spec/docs/superpowers/specs/2026-06-22-ts-dev-proxy-design.md
Plan: https://github.com/IABTechLab/trusted-server/blob/worktree-review-ts-dev-proxy-spec/docs/superpowers/plans/2026-06-22-ts-dev-proxy.md

2. Breakdown the work into tasks in the parent Epic after completing spec and plan.