feat(auth): allow OpenID/OAuth2 logins without a refresh token (AUTH_<PROVIDER>_REQUIRE_REFRESH_TOKEN) - #430

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v3, actions/setup-node@v3, pnpm/action-setup@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/