Initial commit: FA Design System source files

Copy of the Funeral Arranger design system components, theme, tokens,
and Storybook config from the original Parsons project. Pre-upgrade
baseline with React 18, MUI v5, Storybook 8.

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

.storybook/preview.tsx

@@ -0,0 +1,27 @@
+import React from 'react';
+import type { Preview } from '@storybook/react';
+import { ThemeProvider } from '@mui/material/styles';
+import CssBaseline from '@mui/material/CssBaseline';
+import { theme } from '../src/theme';
+import '../src/theme/generated/tokens.css';
+
+const preview: Preview = {
+  decorators: [
+    (Story) => (
+      <ThemeProvider theme={theme}>
+        <CssBaseline />
+        <Story />
+      </ThemeProvider>
+    ),
+  ],
+  parameters: {
+    controls: {
+      matchers: {
+        color: /(background|color)$/i,
+        date: /Date$/i,
+      },
+    },
+  },
+};
+
+export default preview;