The paper's headline claims are intentionally retrieval-only: they cover retrieval performance on two curated prerequisite DAGs (LectureBank-Full and MOOC-CS) plus a distinct-domain fact-graph validation on QASC. End-to-end generation outcomes are reported only as diagnostics of context quality, not as headline results, and an auxiliary denser HotpotQA slice is included as an external-validity boundary check rather than a primary benchmark. Qualitative manual bundles are released for future audits and are explicitly not used to validate automatic judges or to support inferential claims. The abstract makes this scope explicit by stating that adaptive depth gating is treated as an optional extension rather than a core claim, while diffusion with role-aware quotas serves only as a controlled test case.