feat(server): inbound operator-write pipeline — OnWriteValue authz gate + node-write router

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/Security/OpcUaDataPlaneRoles.cs

@@ -22,4 +22,10 @@ public static class OpcUaDataPlaneRoles
     /// route the command to the engine; absent it, the call is denied with
     /// <c>BadUserAccessDenied</c>.</summary>
     public const string AlarmAck = "AlarmAck";
+
+    /// <summary>The role that grants authority to write a writable equipment-tag variable node
+    /// (FreeAccess / Operate attributes). A session must carry this role for the inbound
+    /// <c>OnWriteValue</c> handler (Task 11) to route the value to the backing driver; absent it the
+    /// write is denied with <c>BadUserAccessDenied</c> before any driver call.</summary>
+    public const string WriteOperate = "WriteOperate";
 }