WithOtOpcUaRuntimeActors no longer builds a ClusterClient from
MeshTransport:CentralContactPoints, and NodeCommunicationActor.Props takes only the gRPC
IApplyAckSender. The ackRouter gate narrows from `useClusterClient || useGrpc` to `useGrpc`,
and the CentralClusterClientName constant is gone.
NodeCommunicationActor's no-transport warning now names MeshTransport:CentralGrpcEndpoints
and MeshTransport:Mode only — the old text pointed an operator at a key that no longer
exists.
Ripples in this step: the two ClusterClient-shaped facts in NodeCommunicationActorTests
(Send-not-SendToAll, and sender-wins-over-a-client) are deleted — the first has no subject
left, the second guarded a both-transports-present state that is now unconstructible. The
Runtime ServiceCollectionExtensions fact keeps its ackRouter pin and drops its
"no ClusterClient actor exists" half for the same reason.
Joseph Doherty
ab5b958d47