Add storefront component migration: cards, badges, progress bars, animations, and React wrapper package

Major feature migration from dt-shopify-storefront into the design system:

- Card system: per-card color modes (normal/emphasis/warning/success/other),
  progress bars, full-bleed card body (card-body-flush), image bevel clip-paths,
  and visible structural borders at bevel corners
- Badge system: dt-card-badge with position-aware offsets for cards vs media frames
- Media frames: dt-bevel-media with inner surface fill, image clipping, and
  "MISSING MEDIA" placeholder for empty containers
- Interactive bevel buttons: dt-btn with hover/selected states and pulse animation
- Menu items: dt-menu-item with active states and level indentation
- Animations: scale-in, fade-in, slide-up, pulse, ping, spin keyframes
- Feature legend: CSS grid for product feature icons with state colors
- Scrollbar styling for DT brand
- New @dangerousthings/react package wrapping web CSS components
- New @dangerousthings/tailwind-preset package
- New @dangerousthings/hex-background package
- Desktop showcase rewritten in React with Tailwind CSS
- Mobile showcase updated with new screens (animations, filters, advanced cards)
- Tokens: added mode color tokens, RGB variants, and selected-state tokens

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/showcase/desktop/package.json

@@ -24,13 +24,24 @@
     "clean": "rm -rf dist release"
   },
   "dependencies": {
+    "@dangerousthings/react": "*",
     "@dangerousthings/tokens": "*",
-    "@dangerousthings/web": "*"
+    "@dangerousthings/web": "*",
+    "react": "^18.0.0",
+    "react-dom": "^18.0.0",
+    "react-icons": "^5.6.0"
   },
   "devDependencies": {
+    "@dangerousthings/tailwind-preset": "*",
+    "@types/react": "^18.2.0",
+    "@types/react-dom": "^18.2.0",
+    "@vitejs/plugin-react": "^4.0.0",
+    "autoprefixer": "^10.4.0",
     "concurrently": "^9.0.0",
     "electron": "33.4.11",
     "electron-builder": "^25.0.0",
+    "postcss": "^8.4.0",
+    "tailwindcss": "^3.4.0",
     "typescript": "^5.8.3",
     "vite": "^6.0.0",
     "wait-on": "^8.0.0"