The Jekyll al-folio theme requires a working Jupyter installation to successfully build the site. The default Cloudflare Pages Jekyll builder does not include a Jupyter installation. Instead of building the site on the Cloudflare platform, one can build and deploy the site using GitHub Actions.
In order to utilize both Production and Preview deployments in Cloudflare Pages, update the .github/workflows/broken-links.yml workflow to include the desired development branch(es), and utilize the github.event.workflow_run.head_branch attribute in the checkout and delpoy steps within deploy.yml.