refactor(Timestamp): 规范化页面组件目录结构

- 将子组件移至 components/ 子目录（LiveClock、ResultView）
- 创建 __tests__/ 目录结构
- 更新所有相关导入路径

Co-authored-by: Cursor <cursoragent@cursor.com>

src/pages/Timestamp/__tests__/index.test.tsx

@@ -0,0 +1,11 @@
+import { render, screen } from '@testing-library/react';
+import { describe, it, expect } from 'vitest';
+import Index from '../index';
+
+describe('Timestamp 页面', () => {
+  it('应该渲染页面标题', () => {
+    render(<Index />);
+    // 基本渲染测试
+    expect(screen.getByRole('button')).toBeInTheDocument();
+  });
+});