fix-node-mirror

Configure npm, yarn, and pnpm to use China-based registry mirrors (npmmirror/Taobao, Tencent Cloud, TUNA, USTC) for faster package installation. Use this skill whenever npm install, yarn install, or pnpm install is slow or timing out in China, when ETIMEDOUT or ECONNREFUSED errors appear from registry.npmjs.org, or when setting up a Node.js development environment in China. If the user says "npm 太慢", "yarn 超时", or similar, always use this skill.