fix(data-connection-layer): resolve DataConnectionLayer-014..017 — real logger for OPC UA client, initial-connect failover, accurate subscribe response, per-tag write-batch results

src/ScadaLink.DataConnectionLayer/Adapters/RealOpcUaClient.cs

@@ -316,11 +316,24 @@ public class RealOpcUaClientFactory : IOpcUaClientFactory
 {
     private readonly OpcUaGlobalOptions _globalOptions;
 
+    // DataConnectionLayer-014: a real logger must be threaded through to every
+    // RealOpcUaClient this factory builds, otherwise the DCL-012 auto-accept-certificate
+    // warning emitted in RealOpcUaClient.ConnectAsync sinks into NullLogger and is never
+    // seen in production. The factory is constructed by DataConnectionFactory, which has
+    // an ILoggerFactory available.
+    private readonly ILoggerFactory _loggerFactory;
+
     public RealOpcUaClientFactory() : this(new OpcUaGlobalOptions()) { }
+
     public RealOpcUaClientFactory(OpcUaGlobalOptions globalOptions)
+        : this(globalOptions, NullLoggerFactory.Instance) { }
+
+    public RealOpcUaClientFactory(OpcUaGlobalOptions globalOptions, ILoggerFactory loggerFactory)
     {
         _globalOptions = globalOptions;
+        _loggerFactory = loggerFactory;
     }
 
-    public IOpcUaClient Create() => new RealOpcUaClient(_globalOptions);
+    public IOpcUaClient Create() =>
+        new RealOpcUaClient(_globalOptions, _loggerFactory.CreateLogger<RealOpcUaClient>());
 }