fix(site-runtime): publish quality changes to site stream for real-time debug view updates

HandleConnectionQualityChanged now publishes AttributeValueChanged events
to the SiteStreamManager for all affected attributes. This ensures the
central UI debug view updates in real-time when a data connection
disconnects and attributes go bad quality.

Only publishes to the stream — does NOT notify script or alarm actors,
since the value hasn't changed and firing scripts/alarms on quality-only
changes would cause spurious evaluations.

src/ScadaLink.SiteRuntime/Actors/InstanceActor.cs

@@ -301,6 +301,10 @@ public class InstanceActor : ReceiveActor
         if (_configuration == null) return;
 
         // Mark all attributes bound to this connection with the new quality
+        // and publish to the site stream so the debug view updates in real-time.
+        // We intentionally do NOT notify script/alarm actors here — the value
+        // hasn't changed, only the quality, and firing scripts/alarms would
+        // cause spurious evaluations.
         var qualityStr = qualityChanged.Quality.ToString();
         foreach (var attr in _configuration.Attributes)
         {
@@ -309,6 +313,16 @@ public class InstanceActor : ReceiveActor
             {
                 _attributeQualities[attr.CanonicalName] = qualityStr;
                 _attributeTimestamps[attr.CanonicalName] = qualityChanged.Timestamp;
+
+                // Publish quality change to stream (current value, new quality)
+                _attributes.TryGetValue(attr.CanonicalName, out var currentValue);
+                _streamManager?.PublishAttributeValueChanged(new AttributeValueChanged(
+                    _instanceUniqueName,
+                    attr.DataSourceReference,
+                    attr.CanonicalName,
+                    currentValue,
+                    qualityStr,
+                    qualityChanged.Timestamp));
             }
         }
     }