preflight check in deploy-website.sh

Add a section to the script deploy-website.sh "preflight check".

- The most recent 'develop' branch workflow CI was green.
- No actions workflows are currently in-progress in either the `master` or the `develop` branch.

In other words, don't deploy to production unless it's mostly guaranteed to be successful. And if other jobs are running, wait for them to complete (and without errors) before proceeding.

Start by reading deploy-website.sh and identify where deployment begins. Inspect how the repository exposes workflow status for the develop and master branches, then add the preflight section so deployment proceeds only after the latest develop CI is green and no relevant workflows remain in progress. Done means both checks block unsafe deployment and allow a deployment when their conditions are satisfied.

Written by the indexing model from the issue text.