feat(plugins): 声明式版本管理器 toolchainSources，自动发现 mise 等安装的运行时并按项目版本选择 - #1581

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-node@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/