fix(light): keep the last state when a light reports an unknown WHAT - #456

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea, actions/setup-python@v5, actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

A test tried to use socket.socket.connect() with host "192.168.1.50" (allowed: "127.0.0.1").