Add configurable transport security profiles and bind address

Adds Security section to appsettings.json with configurable OPC UA
transport profiles (None, Basic256Sha256-Sign, Basic256Sha256-SignAndEncrypt),
certificate policy settings, and a configurable BindAddress for the
OPC UA endpoint. Defaults preserve backward compatibility.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ZB.MOM.WW.LmxOpcUa.Host/OpcUaServiceBuilder.cs

@@ -122,6 +122,17 @@ namespace ZB.MOM.WW.LmxOpcUa.Host
             return this;
         }
 
+        /// <summary>
+        /// Sets the security profile configuration for the test host.
+        /// </summary>
+        /// <param name="security">The security profile configuration to inject.</param>
+        /// <returns>The current builder so additional overrides can be chained.</returns>
+        public OpcUaServiceBuilder WithSecurity(SecurityProfileConfiguration security)
+        {
+            _config.Security = security;
+            return this;
+        }
+
         /// <summary>
         /// Effectively disables Galaxy change detection by pushing the polling interval beyond realistic test durations.
         /// </summary>