add FX_BM26 subprotocol for BM26 P51, stunt flag for SkyViper Vector and optical flow sensor for XK K270 - #1168

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, arduino/setup-arduino-cli@v2. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/