Integrate impeccable design quality tools

Selective integration from pbakaus/impeccable (Apache 2.0):

Reference material (docs/reference/impeccable/):
- 7 design guides: typography, color-and-contrast, spatial-design,
  motion-design, interaction-design, responsive-design, ux-writing
- 3 critique references: cognitive-load, heuristics-scoring, personas
- 4 skill references for internal use: audit, critique, polish,
  frontend-design (anti-patterns list)

New skills:
- /audit — technical quality scoring (0-20) across 5 dimensions:
  accessibility, performance, theming, responsive, design quality
- /critique — UX design review using Nielsen's 10 heuristics (0-40),
  adapted for FA's sensitive audience context

Updated skills:
- /review-component — added interactive states checklist and design
  anti-patterns checklist (8 checks each)
- /preflight — added visual QA spot-check section (transitions,
  focus-visible, touch targets, spacing consistency)

No code changes — all existing components, tokens, and theme untouched.

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

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

@@ -46,4 +46,22 @@ Review a component against FA Design System conventions and report pass/fail for
 - [ ] Long content / overflow
 - [ ] autodocs tag present
 
+### Interactive states (ref: docs/reference/impeccable/interaction-design.md)
+- [ ] Default (resting) state is styled
+- [ ] Hover state provides visual feedback (not just cursor change)
+- [ ] Focus-visible state is distinct from hover (keyboard users never see hover)
+- [ ] Active/pressed state feels responsive
+- [ ] Disabled state is visually diminished but still distinguishable
+- [ ] Transitions use 150ms ease-in-out (FA convention)
+
+### Design anti-patterns (ref: docs/reference/impeccable/frontend-design-skill.md)
+- [ ] No grey text on coloured backgrounds (use a shade of the background colour instead)
+- [ ] No cards nested inside cards (flatten hierarchy with spacing/typography)
+- [ ] No identical card grids with zero variation (vary content, size, or emphasis)
+- [ ] No bounce/elastic easing (use ease-out-quart or ease-in-out)
+- [ ] Not every button is primary (use variant hierarchy: contained > soft > outlined > text)
+- [ ] No redundant copy (headings don't restate content below them)
+- [ ] No glassmorphism/blur used purely as decoration
+- [ ] Whitespace is intentional, not leftover
+
 **Report format:** List each check with pass/fail and specific issues found. End with a summary and recommended fixes.