fix(BACKEND-TENSTORRENT-QWEN35): EnsureDevice2D consumed stale host bytes under host-free decode; Qwen3.5-0.8B sacred gate 16/16 on ambient - #1768

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. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/