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/react/src/components/DTSwitch.tsx

@@ -0,0 +1,44 @@
+/**
+ * DTSwitch — Angular toggle switch.
+ *
+ * CSS reference: forms-dt.css .dt-switch, .dt-switch-track, .dt-switch-thumb
+ */
+
+import type { CSSProperties } from 'react';
+import { cx } from '../utils/cx';
+
+interface DTSwitchProps {
+  checked: boolean;
+  onChange: (checked: boolean) => void;
+  disabled?: boolean;
+  label?: string;
+  className?: string;
+  style?: CSSProperties;
+}
+
+export function DTSwitch({
+  checked,
+  onChange,
+  disabled = false,
+  label,
+  className,
+  style,
+}: DTSwitchProps) {
+  return (
+    <div
+      className={cx('dt-switch-wrapper', className)}
+      style={{ display: 'inline-flex', alignItems: 'center', gap: '12px', ...style }}>
+      <label className="dt-switch">
+        <input
+          type="checkbox"
+          checked={checked}
+          onChange={e => onChange(e.target.checked)}
+          disabled={disabled}
+        />
+        <span className="dt-switch-track" />
+        <span className="dt-switch-thumb" />
+      </label>
+      {label && <span>{label}</span>}
+    </div>
+  );
+}