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

src/ZB.MOM.WW.ScadaBridge.HealthMonitoring/CentralHealthAggregator.cs

@@ -196,6 +196,20 @@ public class CentralHealthAggregator : BackgroundService, ICentralHealthAggregat
         return state;
     }
 
+    /// <inheritdoc />
+    public void PruneUnknownSites(IReadOnlyCollection<string> knownSiteIds)
+    {
+        var known = new HashSet<string>(knownSiteIds, StringComparer.Ordinal);
+        foreach (var siteId in _siteStates.Keys)
+        {
+            if (siteId == CentralHealthReportLoop.CentralSiteId || known.Contains(siteId))
+                continue;
+            if (_siteStates.TryRemove(siteId, out _))
+                _logger.LogInformation(
+                    "Site {SiteId} evicted from health aggregator (no longer configured)", siteId);
+        }
+    }
+
     /// <inheritdoc />
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {