fix(client): Authentication v2: auth/login + auth/logout - #126

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955, actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00, gradle/gradle-build-action@a8f75513eafdebd8141bd1cd4e30fcd194af8dfa. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/