[tinker] 13/n towards Kimi K2.6: adapter-only colocated weight sync for Tinker API LoRA (merge_lora=false) - #2064

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/