fix: skip index build when a source produces no text chunks - #320

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c, codecov/test-results-action@1b5b448b98e58ba90d1a1a1d9fcb72ca2263be46. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/