feat(storybook): add background options for light and dark themes

- Introduced background parameters in Storybook preview configuration to support light and dark themes.
- Defined specific color values for each theme to enhance visual consistency during component development.

packages/ui/.storybook/preview.tsx

@@ -4,6 +4,14 @@ import { withThemeByClassName } from '@storybook/addon-themes'
 import type { Preview } from '@storybook/react'
 
 const preview: Preview = {
+  parameters: {
+    backgrounds: {
+      options: {
+        light: { name: 'Light', value: 'hsla(0, 0%, 97%, 1)' },
+        dark: { name: 'Dark', value: 'hsla(240, 6%, 10%, 1)' }
+      }
+    }
+  },
   decorators: [
     withThemeByClassName({
       themes: {