Add design council skill and interaction-and-feedback contract

AGENTS.md

@@ -62,7 +62,7 @@ src/
 styles/              # Global CSS (tokens, base)
 docs/
 ├── spec/            # Authoritative behavioral specification (00–10) — the WHAT
-├── architecture/    # Architecture playbook (00–09) — the HOW (self-contained)
+├── architecture/    # Architecture playbook (00–10) — the HOW (self-contained)
 │   └── visual-specimen.html  # Standalone token sandbox + reusable-primitive catalog
 ├── IMPLEMENTATION-PLAN.md    # Milestone sequence (M0–M6)
 └── WHY-A-SEPARATE-REBUILD.md
@@ -115,6 +115,10 @@ Invoke with `/<name>` (defined in `.claude/skills/`):
   `// TODO:` breadcrumbs at code sites for out-of-scope observations.
 - **`/doc-update`** — capture session-discovered knowledge gaps into the right doc layer
   (`docs/spec/` for behavior, `docs/architecture/` for patterns).
+- **`/council`** — consult the design council (Carbon, GOV.UK, WAI-ARIA APG, Nielsen
+  Norman, cloned under `reference/`) before a user-facing interaction/content/a11y
+  decision. Auto-fires on error/empty-state copy and new interactive-widget keyboard/focus
+  work; on demand otherwise. It advises; `docs/architecture/09`+`10` decide.
 - **`/release`** — bump version, update the changelog, prepare a git tag.
 
 ### Versioning