feat(dss-ui): Button component with design tokens only

- Button.css uses only CSS custom properties, no fallbacks
- Token validator now blocks hardcoded values (strict_mode: true)
- Hook scripts converted from ESM (.js) to CommonJS (.cjs)
- Storybook unified config with HMR disabled for nginx proxy
- Added dss-ui package with Figma-synced components and stories

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

packages/dss-ui/stories/SelectMenuGroupLabel.stories.tsx

@@ -0,0 +1,46 @@
+/**
+ * Select Menu Group Label Stories
+ * @generated 2025-12-11T14:37:52.624900
+ */
+import type { Meta, StoryObj } from '@storybook/preact';
+import { SelectMenuGroupLabel, type SelectMenuGroupLabelProps } from '../src/atoms/SelectMenuGroupLabel';
+
+const meta: Meta<SelectMenuGroupLabelProps> = {
+  title: '2. Atoms/SelectMenuGroupLabel',
+  component: SelectMenuGroupLabel,
+  tags: ['autodocs'],
+  parameters: {
+    docs: {
+      description: {
+        component: `Auto-generated SelectMenuGroupLabel component
+
+**Classification:** atom
+**Slots:** label
+**Figma ID:** 80:10189`
+      }
+    }
+  },
+  argTypes: {
+    type: {
+      control: 'select',
+      options: ['Regular', 'Small'],
+      description: 'Type variant',
+    },
+    indented: {
+      control: 'select',
+      options: ['false', 'true'],
+      description: 'Indented variant',
+    },
+  },
+};
+
+export default meta;
+type Story = StoryObj<SelectMenuGroupLabelProps>;
+
+export const Default: Story = {
+  args: {
+    type: 'Regular',
+    indented: 'false',
+    children: 'SelectMenuGroupLabel'
+  },
+};