构建脚本不支持跨平台，不适配windows

**Version information (版本信息)**
- ChatUI
- ChatUI Version: 3.0.1
- React Version: 17.0.2
- OS Version: Windows11
- Browser Version: Google Chrome 138.0.7204.101

**Describe the bug (描述问题)**
执行pnpm build时触发clean、js:cjs和js:esm 脚本
clean脚本问题：在windows下不存在rm
js:cjs和js:esm脚本问题：在windows不支持直接设置环境变量

**Steps To Reproduce (重现步骤)**
1. 在项目根目录执行pnpm build

**Link to minimal reproduction (最小化重现链接)**

**Expected behavior (期望的结果是什么)**
适配windows

Start by inspecting the project’s build scripts invoked by `pnpm build`, especially `clean`, `js:cjs`, and `js:esm`, and reproduce the command on Windows 11. Done means the clean step and both JavaScript build steps run successfully on Windows, allowing `pnpm build` to complete.

Written by the indexing model from the issue text.