[CHORE] Healthcheck for Supabase DBs

[omshub-admin]

Add a basic healthcheck endpoint (and corresponding GitHub-Action-based caller) for prod and dev DBs in Supabase to prevent projects from going stale and getting paused (and, eventually/ultimately, auto-deleted by Supabase 😬)

[github-actions]

This issue is stale because it has been open for 60 days with no activity.