Redesign storefront to match minimal reference design

Product cards, header, footer, PDP, and typography reworked toward a
leaner layout; adds shop policy pages backed by the Storefront API.

- Type: switch to Geist Sans/Mono, regular-weight headings
- Product cards: drop borders, rounded corners, and action buttons
- Header: shorter bar, no bottom border, center-out hover underline,
  bag icon replacing the cart icon (drawer wording updated to match)
- Footer: single line with policy links and social icons on bg-background
- Policies: /policies/[handle] renders shop.privacyPolicy,
  termsOfService, refundPolicy, shippingPolicy, subscriptionPolicy
  (SSG, hourly revalidation)
- PDP: image grid with mobile carousel + dots and click-to-zoom,
  sticky info column, colour swatches from option optionValues with a
  configurable name-to-colour fallback in config/swatches.ts,
  Shop-purple checkout button
- Recommendations: left-aligned heading on bg-background
- Ignore .env*.local and tsconfig.tsbuildinfo

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016jWbNNJLksC1QG8z8845FX

.gitignore

@@ -3,3 +3,5 @@ node_modules/*
 .next
 next-env.d.ts
 .yarn/install-state.gz
+.env*.local
+tsconfig.tsbuildinfo