Add workflow infrastructure — ESLint, Prettier, Husky, Vitest, 7 new skills

Phase 1: Session log archived (1096→91 lines), D031 token access convention
Phase 2: ESLint v9 + Prettier + jsx-a11y, initial config and lint fixes
Phase 3: 7 new skills (polish, harden, normalize, clarify, typeset, quieter, adapt)
         + Vercel reference docs, updated audit/review-component refs
Phase 4: Husky + lint-staged pre-commit hooks, preflight updated to 8 checks
Phase 5: Vitest + Testing Library + /write-tests skill

- Badge.tsx colour maps unified to CSS variables (D031)
- 5 empty interface→type alias fixes (Switch, Radio, Divider, IconButton, Link)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.claude/skills/review-component/SKILL.md

@@ -13,6 +13,7 @@ Review a component against FA Design System conventions and report pass/fail for
 2. Read `docs/conventions/token-conventions.md` for token usage rules
 3. Read the component source file in `src/components/`
 4. Read the component's Storybook stories
+5. Reference `docs/reference/vercel/react-best-practices.md` for React performance patterns (optional, for deeper code quality review)
 
 **Check each of these and report pass/fail:**