fix(health): evict deleted sites from the aggregator on the periodic site refresh

src/ZB.MOM.WW.ScadaBridge.Communication/Actors/CentralCommunicationActor.cs

@@ -499,7 +499,12 @@ public class CentralCommunicationActor : ReceiveActor
             var frozen = contacts.ToDictionary(
                 kvp => kvp.Key,
                 kvp => (IReadOnlyList<string>)kvp.Value.AsReadOnly());
-            return new SiteAddressCacheLoaded(frozen);
+
+            // Carry the full configured-site identifier set (not just the
+            // address-bearing subset in `frozen`) so the aggregator prunes only
+            // genuinely-deleted sites and never an addressless-but-configured one.
+            var knownSiteIds = sites.Select(s => s.SiteIdentifier).ToList();
+            return new SiteAddressCacheLoaded(frozen, knownSiteIds);
         }).PipeTo(self);
     }
 
@@ -570,6 +575,12 @@ public class CentralCommunicationActor : ReceiveActor
         }
 
         _log.Info("Site ClusterClient cache refreshed with {0} site(s)", _siteClients.Count);
+
+        // Self-healing eviction: a site deleted from configuration would otherwise
+        // linger in the aggregator as a permanently-offline tile (and live KPI
+        // sample source) forever. Prune on every refresh so it disappears within
+        // one refresh interval without needing a dedicated deletion event.
+        _serviceProvider.GetService<ICentralHealthAggregator>()?.PruneUnknownSites(msg.KnownSiteIds);
     }
 
     // TrackMessageForCleanup removed — the dicts it fed
@@ -650,7 +661,9 @@ public record RefreshSiteAddresses;
 /// discipline. The producer wraps the constructed buckets with
 /// <c>List&lt;T&gt;.AsReadOnly()</c> before piping to Self.
 /// </summary>
-internal record SiteAddressCacheLoaded(IReadOnlyDictionary<string, IReadOnlyList<string>> SiteContacts);
+internal record SiteAddressCacheLoaded(
+    IReadOnlyDictionary<string, IReadOnlyList<string>> SiteContacts,
+    IReadOnlyCollection<string> KnownSiteIds);
 
 /// <summary>
 /// Notification sent to debug view subscribers when the stream is terminated