docs: 修复文档中 ReactDOM 引入错误的问题

[demigodliu]

Checklist

• npm test passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Description of change

修复示例代码中 ReactDOM 导入路径错误。

之前示例中错误地从 react 导入了 ReactDOM，导致运行时错误，因为 React 默认导出不包含渲染相关方法。
此次更新改为从 react-dom 导入，恢复了与 React 16 渲染 API 的兼容性，确保示例代码能够正常运行。

[gemini-code-assist]

Summary of Changes

Hello @demigodliu, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

此拉取请求旨在修复文档中一个关键的导入错误，该错误导致 React 示例代码无法正确执行。通过将 ReactDOM 的导入源从 react 更正为 react-dom，确保了示例的兼容性和功能性，提升了用户在学习和使用 F2 框架时体验。

Highlights

• 修复文档示例中的 ReactDOM 导入错误: 将 site/docs/tutorial/framework/react.zh.md 文件中的 ReactDOM 导入路径从 react 更正为 react-dom，以确保 React 示例代码能够正常运行。

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[gemini-code-assist]

Code Review

您好！感谢您对文档的贡献。本次 PR 修复了 React 示例代码中 ReactDOM 导入路径错误的问题，这是一个非常及时的修正，确保了示例代码的可运行性。代码变更本身是完全正确的。

此外，我注意到示例中使用了在 React 18 中已被弃用的 ReactDOM.render API。我已在相关代码行添加了一条评论，建议未来可以考虑更新到新的 createRoot API，以保持示例代码的现代性。这只是一个着眼于未来的建议，不影响本次合并。

总体而言，这是一次高质量的修复，做得很好！