feat(site): support system theme-mode auto switch

[HaixingOoO]

🤔 这个 PR 的性质是？

• [ ] 日常 bug 修复
• [x] 新特性提交
• [ ] 文档改进
• [ ] 演示代码改进
• [ ] 组件样式/交互改进
• [ ] CI/CD 改进
• [ ] 重构
• [ ] 代码风格优化
• [ ] 测试用例
• [ ] 分支合并
• [ ] 其他

🔗 相关 Issue

💡 需求背景和解决方案

官网支持自动切换系统主题

📝 更新日志

• feat(site): support system theme-mode auto switch

• [x] 本条 PR 不需要纳入 Changelog

☑️ 请求合并前的自查清单

⚠️ 请自检并全部勾选全部选项。⚠️

• [x] 文档已补充或无须补充
• [x] 代码演示已提供或无须提供
• [x] TypeScript 定义已补充或无须补充
• [x] Changelog 已提供或无须提供

[tencent-adm]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[pkg-pr-new[bot]]

Open in StackBlitz

npm i https://pkg.pr.new/Tencent/tdesign/@tdesign/site-components@742

npm i https://pkg.pr.new/Tencent/tdesign/tdesign-theme-generator@742

commit: 6e2d1a1

[tdesign-bot]

TDesign Component Site Preview CI Open

Sites (8)

Component	Preview
tdesign-site
tdesign-vue
tdesign-react
tdesign-vue-next
@tdesign-vue-next/chat
tdesign-mobile-vue
tdesign-mobile-react
tdesign-miniprogram