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v2-ci / unit-tests (push) Has been cancelled
IOpcUaEndpointState (review-remediation lane C3) recorded whether the SDK started, but only the health check read it: a fused node whose endpoint failed (port 4840 taken, ...) still advertised 250/240 and stayed driver Primary, so the Primary-gated data plane ran on a node no client could reach while the reachable peer refused writes as Secondary. - Move IOpcUaEndpointState/OpcUaEndpointState/OpcUaEndpointStatus from Host to Commons.OpcUa so the Runtime can consume it. - ServiceLevelCalculator: new NodeHealthInputs.EndpointListening (default true). false -> 0, ahead of every other input including the +10 Primary bonus. - OpcUaPublishActor: takes the endpoint state, feeds EndpointListening (Failed only; NotStarted / Stopped are boot/shutdown windows) on the DB-backed and DB-less paths, and the legacy role-only seam returns 0 for a failed endpoint too. - New OpcUaEndpointStepDownActor (one per driver node): a Primary (ClusterActiveNode.SelfIsActive, the election's own primitive) with a Failed endpoint gracefully Leaves its mesh - the manual failover mechanism - so the peer becomes the oldest Up driver member, hosts the singletons and is Primary. The election itself is not bent. Guarded on a peer having recently reported its own endpoint listening (EndpointReport on the new opcua-endpoint-state DPS topic), so a pair with both endpoints failed does not bounce the role and restart nodes forever, and a lone node never shuts itself down. - Runtime now references ZB.MOM.WW.Health.Akka (ClusterActiveNode). - Docs: Redundancy.md tier table + new "Endpoint start failure: Primary step-down" section; cluster-topology rule; HealthEndpoints / OpcUaEndpointHealthCheck comments (F-C1 landed). Tests: ServiceLevelCalculatorTests (+5), OpcUaPublishActorEndpointStateTests (7: DB-less, DB-backed, legacy seam, NotStarted/Stopped do not demote, a later failure demotes on the next tick), OpcUaEndpointStepDownActorTests (3, real two-node mesh: holds while the peer is not listening then leaves and the peer becomes Primary; failed Secondary and healthy Primary never leave). Each was mutation-checked: removing the calculator/legacy guard, the Leave, the peer-listening guard or the Primary guard fails the corresponding tests.