emrg: gui renderer — FileTree nested-dir load failure now shows error hint (regression from #999 review) - #1005

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: astral-sh/setup-uv@v5. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/