P9 Interpretability: audit against the rubric

[breimanntools]

Problem

Protocol 9 already carries three plots and needs the same recorded audit.

The protocol quality rubric lives at docs/guides/protocol_quality_rubric.md. Protocol 1 is the exemplar: every core concept is shown, not asserted.

Goal

Bring this protocol to the teaching standard set by Protocol 1: each core concept is shown, not asserted.

Requirements

• A recorded audit against each rubric point
• Any gap closed in the same change
• Re-executed with committed outputs if anything changes

KPIs / Acceptance criteria

• The protocol passes every point of the rubric in review
• The rendered page shows the new figure or figures
• The protocol's skeleton and narrative order are unchanged

Scope / non-goals

• Core. No new dependency.
• A visualization and prose pass, not a rewrite of the workflow.
• Note: a changed first figure invalidates the gallery thumbnail, which must be regenerated in the same change.

Child of #455.