Storybook on Vite + Storybook 10; ESM-only package; flat-config lint - #431

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, actions/setup-node@v4, ataylorme/eslint-annotate-action@2.2.0, tspascoal/get-user-teams-membership@v2. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/