fix(metaharness): use the @metaharness/* and ruflo CLI already installed instead of npm-installing at tool-call time (#3366) - #3367

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/