fix: initialize SDK telemetry and preserve ByteString boundaries

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OpcUaApplicationHost.cs

@@ -173,6 +173,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
     private readonly ILogger<OpcUaApplicationHost> _logger;
     private ApplicationInstance? _application;
     private StandardServer? _server;
+    private readonly ITelemetryContext _telemetry = DefaultTelemetry.Create(_ => { });
     private readonly List<IUserTokenAuthenticator> _identityAuthenticators = [];
 
     /// <summary>Initializes a new instance of the OPC UA application host.</summary>
@@ -205,7 +206,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
         // 1.5.378 requires an ITelemetryContext on the ApplicationInstance ctor (the parameterless ctor
         // is obsolete). DefaultTelemetry.Create wires the SDK's internal logging; an empty builder keeps
         // the SDK's trace off our ILogger (the host keeps its own _logger) — sufficient for the bootstrap.
-        _application = new ApplicationInstance(DefaultTelemetry.Create(_ => { }))
+        _application = new ApplicationInstance(_telemetry)
         {
             ApplicationName = _options.ApplicationName,
             ApplicationType = ApplicationType.Server,
@@ -487,7 +488,7 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
         serverConfig.SecurityPolicies = BuildSecurityPolicies(_options.EnabledSecurityProfiles).ToArray();
         serverConfig.UserTokenPolicies = BuildUserTokenPolicies(_options.AllowAnonymous).ToArray();
 
-        var config = new ApplicationConfiguration
+        var config = new ApplicationConfiguration(_telemetry)
         {
             ApplicationName = _options.ApplicationName,
             ApplicationUri = _options.ApplicationUri,

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs

@@ -6574,7 +6574,7 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
         return leaf switch
         {
             // BaseEventType/EventId is a ByteString — encode the driver-specific string id as UTF-8 bytes.
-            "EventId" => new Variant(System.Text.Encoding.UTF8.GetBytes(evt.EventId ?? string.Empty)),
+            "EventId" => Variant.From(ByteString.From(System.Text.Encoding.UTF8.GetBytes(evt.EventId ?? string.Empty))),
             "EventType" => new Variant(eventType),
             "SourceName" => evt.SourceName is null ? Variant.Null : new Variant(evt.SourceName),
             "SourceNode" => SourceNodeOf(evt) is { } source ? new Variant(source) : Variant.Null,

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/SdkValueBoundary.cs

@@ -14,7 +14,9 @@ internal static class SdkValueBoundary
             if (array.Rank != 1) throw new ArgumentException("Only one-dimensional values are supported.", nameof(value));
             value = array.Clone();
         }
-        if (byteArray && value is byte[] bytes) return Variant.From((ArrayOf<byte>)bytes);
+        if (value is byte[] bytes) return byteArray
+            ? Variant.From((ArrayOf<byte>)bytes)
+            : Variant.From(ByteString.From(bytes));
         if (VariantHelper.TryCastFrom(value, out var variant)) return variant;
         throw new ArgumentException("Unsupported OPC UA value type.", nameof(value));
     }