Why: RDM and Frontend units must implement one citation interface. Evidence: Derived from the merged U6 evidence batch model (RDM 703e41d) and current cockpit/inspect read models. Impact: Spec only. Refs: docs/superpowers/plans/2026-10-18-regulations-knowledge-base-plan.md U7 Co-authored-by: Cursor <cursoragent@cursor.com>