An OPC UA server advertises its base address from its own config, not the route
the client took — commonly a 0.0.0.0 wildcard bind or an internal container/NAT
hostname. The OPC Foundation session dials EndpointDescription.EndpointUrl
verbatim, so a 0.0.0.0 advertisement resolved to the client's own loopback and
the connect failed. RealOpcUaClient now swaps the advertised authority for the
reachable host/port (ConnectAsync + VerifyEndpointAsync), preserving scheme+path;
no-op when already reachable. Surfaced live-gating OtOpcUa v3 (#14).
Joseph Doherty
a1abbff760