clusterClientWithNode

Constructs a ClusterClient wrapping raftNode directly.

This is the primary construction path for:

• Tests — pass a FakeRaftNode from :kuilt-raft-test or a sim-wired real RaftNode from MultiNodeRaftSim.

• Callers managing their own transport — construct a RaftNode over a SeamRaftTransport, then wrap it here.

The S3b CoroutineScope.clusterClient extension will be the production relay-room entry point once the Seam-reconnect transport adapter is available.