fix(dcl): format ArrayValue objects as comma-separated strings for display

ArrayValue from LmxProxy client was showing as type name in debug views.
Added ValueFormatter utility and NormalizeValue in LmxProxyDataConnection
to convert arrays at the adapter boundary. DateTime arrays remain as
"System.DateTime[]" due to server-side v1 string serialization.

src/ScadaLink.Communication/Actors/StreamRelayActor.cs

@@ -3,6 +3,7 @@ using Akka.Actor;
 using Akka.Event;
 using Google.Protobuf.WellKnownTypes;
 using ScadaLink.Commons.Messages.Streaming;
+using ScadaLink.Commons.Types;
 using ScadaLink.Communication.Grpc;
 using AlarmState = ScadaLink.Commons.Types.Enums.AlarmState;
 
@@ -38,7 +39,7 @@ public class StreamRelayActor : ReceiveActor
                 InstanceUniqueName = msg.InstanceUniqueName,
                 AttributePath = msg.AttributePath,
                 AttributeName = msg.AttributeName,
-                Value = msg.Value?.ToString() ?? "",
+                Value = ValueFormatter.FormatDisplayValue(msg.Value),
                 Quality = MapQuality(msg.Quality),
                 Timestamp = Timestamp.FromDateTimeOffset(msg.Timestamp)
             }