Refine XML docs for historian, OPC UA, and tests

src/ZB.MOM.WW.LmxOpcUa.Host/OpcUa/OpcUaServerHost.cs

@@ -46,6 +46,7 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.OpcUa
         /// <param name="config">The endpoint and session settings for the OPC UA host.</param>
         /// <param name="mxAccessClient">The runtime client used by the node manager for live reads, writes, and subscriptions.</param>
         /// <param name="metrics">The metrics collector shared with the node manager and runtime bridge.</param>
+        /// <param name="historianDataSource">The optional historian adapter that enables OPC UA history read support.</param>
         public OpcUaServerHost(OpcUaConfiguration config, IMxAccessClient mxAccessClient, PerformanceMetrics metrics,
             HistorianDataSource? historianDataSource = null)
         {