Raise OSError for UDP server startup failures - #323

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683, actions/setup-python@8d9ed9ac5c53483de85588cdf95a591a75ab9f55, Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/