Auto: opcuaclient-14 — ServerUriArray redundant failover

Closes #286

scripts/e2e/e2e-config.sample.json

@@ -60,6 +60,12 @@
         "historyLookbackSec": 3600
     },
 
+    "opcuaclient": {
+        "$comment": "Optional upstream-redundancy probe (PR-14). When both primaryUrl and secondaryUrl are set, test-opcuaclient.ps1 runs an extra bridged read while both upstreams are reachable. Leave keys absent to skip the redundancy stage. The OtOpcUa server's DriverConfig for the OpcUaClient instance must already have Redundancy.Enabled=true + the same EndpointUrls list; this script doesn't reconfigure the driver.",
+        "primaryUrl": "opc.tcp://localhost:50000",
+        "secondaryUrl": "opc.tcp://localhost:50002"
+    },
+
     "phase7": {
         "$comment": "Virtual tags + scripted alarms. The VirtualNodeId must resolve to a server-side virtual tag whose script reads the modbus InputNodeId and writes VT = input * 2. The AlarmNodeId is the ConditionId of a scripted alarm that fires when VT > 100.",
         "modbusEndpoint": "127.0.0.1:5502",