Add Card atom component

- Create card component tokens (borderRadius, padding, shadow, border, background)
- Build Card component with elevated/outlined variants, interactive hover, padding presets
- Add MUI theme overrides using card tokens (shadow.md resting, border for outlined)
- Create 8 Storybook stories: Default, Variants, Interactive, PaddingPresets,
  PriceCardPreview, ServiceOptionPreview, WithImage, RichContent
- Regenerate token pipeline outputs (7 new card tokens)

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

tokens/component/card.json

@@ -0,0 +1,31 @@
+{
+  "card": {
+    "$description": "Card component tokens — content container with elevation or border. Used by PriceCard, ServiceOption, and other molecule/organism compositions.",
+    "borderRadius": {
+      "$type": "dimension",
+      "$description": "Card corner radius.",
+      "default": { "$value": "{borderRadius.md}", "$description": "8px — standard card rounding" }
+    },
+    "padding": {
+      "$type": "dimension",
+      "$description": "Internal padding for card content area.",
+      "default": { "$value": "{spacing.6}", "$description": "24px — standard card padding (desktop)" },
+      "compact": { "$value": "{spacing.4}", "$description": "16px — compact card padding (mobile, tight layouts)" }
+    },
+    "shadow": {
+      "$description": "Elevation shadows for card variants.",
+      "default": { "$value": "{shadow.md}", "$description": "Medium shadow — resting elevated card" },
+      "hover": { "$value": "{shadow.lg}", "$description": "High shadow — interactive card on hover" }
+    },
+    "border": {
+      "$type": "color",
+      "$description": "Border colours for the outlined card variant.",
+      "default": { "$value": "{color.border.default}", "$description": "Neutral border for outlined cards" }
+    },
+    "background": {
+      "$type": "color",
+      "$description": "Card background colours.",
+      "default": { "$value": "{color.surface.raised}", "$description": "White — standard card background (raised surface)" }
+    }
+  }
+}