Add design council skill and interaction-and-feedback contract

CLAUDE.md

@@ -8,10 +8,15 @@ See @AGENTS.md for project overview, architecture rules, and the AI developer pr
 - **[docs/spec/](docs/spec/)** — authoritative behavioral specification (sections 00–10):
   the **what**. This is the contract; implement to it.
 - **[docs/architecture/](docs/architecture/00-overview.md)** — architecture playbook
-  (00–09): the **how** (state, persistence, modals, routing, rendering, inference,
-  relationships, vega-editor techniques, visual design). Self-contained — no external
-  repo needed. Companion: **[visual-specimen.html](docs/architecture/visual-specimen.html)** —
-  token sandbox + reusable-primitive catalog (open in a browser).
+  (00–10): the **how** (state, persistence, modals, routing, rendering, inference,
+  relationships, vega-editor techniques, visual design, interaction & feedback).
+  Self-contained — no external repo needed. Companion:
+  **[visual-specimen.html](docs/architecture/visual-specimen.html)** — token sandbox +
+  reusable-primitive catalog (open in a browser).
+- **[`/council`](.claude/skills/council/SKILL.md)** — the design council: consult external
+  interaction/content/a11y canon (Carbon, GOV.UK, WAI-ARIA APG, Nielsen Norman, cloned
+  under `reference/`) before a user-facing decision. It advises; our contract (architecture
+  09/10) decides. Resolutions are recorded back into the contract.
 - **[docs/IMPLEMENTATION-PLAN.md](docs/IMPLEMENTATION-PLAN.md)** — incremental milestone
   plan (M0–M6), MVP boundary, per-milestone tests + manual checks, and an architecture
   reference index.