[PoMo] Add CI/CD check for site build before merge

[palladius]

Action Item from Postmortem for Issue #57.
Priority: P1
Type: Prevent
Owner: ricc@

Relates to PostMortem #57

Relates to PostMortem #57

[github-actions]

🤖 Hi @palladius, I've received your request, and I'm working on it now! You can track my progress in the logs for more details.

[palladius]

Added #57 as parent.