7892c622cf
Replace the private SitePairActiveNodeHealthCheck (503 whenever no ActorSystem, no data)
with the shared ZB.MOM.WW.Health ActiveNodeHealthCheck constructed with the site-{SiteId}
role: Degraded (200) during startup per the Health spec, and it publishes
selfAddress/activeRole/activeNode so the Overview dashboard can name the active site node.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV