Negotiate CIMD token endpoint auth method - #6400

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: arduino/setup-task@b91d5d2c96a56797b48ac1e0e89220bf64044611. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/