378962eeb1
The AdminUI OPC UA browse picker connected to the EndpointUrl the server advertised in GetEndpoints verbatim, so behind NAT / a container port publish it dialled the server's private hostname + internal port and failed DNS where the runtime driver (which rewrites per #676) connected. - Move the rewrite to the shared OpcUaEndpointUrlRewriter (.Contracts, pure Uri logic, no SDK dependency) and the policy+mode selection to OpcUaEndpointSelection (.Session leaf). Driver and browser both select through it, so the browse connects exactly where the driver does. - Policy/mode filter, server certificate and strict browse PKI (no auto-accept) are unchanged. - Unit tests: rewrite (host/port differ, same, IPv6 both sides, path kept, port-less, scheme mismatch untouched), browser selection seam. - Live NAT tests (Fixture=opc-plc-nat, OPCUA_NAT_ENDPOINT): browse via a published port with a premise check that the advertised host:port differs and does not resolve, nsu= round-trip, unreachable endpoint fails cleanly, SignAndEncrypt reaches the server and is refused BadCertificateUntrusted. Verified red without the rewrite. Refs #806