chore(design-system): add system time mock to date tests [AR-46279]

packages/design-system/src/components/ds-date-input/ds-date-input.stories.tsx

@@ -1,17 +1,32 @@
 import type { Meta, StoryObj } from '@storybook/react-vite';
 import { useState } from 'react';
 import { expect, screen, userEvent, waitFor, within } from 'storybook/test';
+import { vi } from 'vitest';
 import DsDateInput from './ds-date-input';
 import type { DsDateInputProps } from './ds-date-input.types';
 import styles from './ds-date-input.stories.module.scss';
 
+// Mock system time to January 15, 2026 for consistent test dates
+const MOCK_DATE = new Date('2026-01-15T12:00:00');
+
 const meta: Meta<typeof DsDateInput> = {
 	title: 'Design System/DateInput',
 	component: DsDateInput,
 	tags: ['autodocs'],
 	parameters: {
 		layout: 'centered',
 	},
+	beforeEach: () => {
+		vi.useFakeTimers({
+			// needed,
+			shouldAdvanceTime: true,
+		});
+		vi.setSystemTime(MOCK_DATE);
+
+		return () => {
+			vi.useRealTimers();
+		};
+	},
 };
 
 export default meta;