feat(sitecallaudit): central→site Retry/Discard relay for parked operations

src/ScadaLink.Host/Actors/AkkaHostedService.cs

@@ -446,7 +446,17 @@ akka {{
         // the Site Call Audit actor directly (query, KPIs, detail) — mirrors the
         // SetNotificationOutbox wiring above.
         commService?.SetSiteCallAudit(siteCallAuditProxy);
-        _logger.LogInformation("SiteCallAuditActor singleton created");
+
+        // Task 5 (#22): hand the CentralCommunicationActor to the SiteCallAudit
+        // actor so it can relay operator Retry/Discard on parked cached calls to
+        // the owning site (over the per-site ClusterClient via SiteEnvelope).
+        // Mirrors the RegisterAuditIngest / RegisterNotificationOutbox wiring;
+        // the message is sent to the singleton proxy so it reaches whichever
+        // central node currently hosts the singleton.
+        siteCallAuditProxy.Tell(
+            new ScadaLink.SiteCallAudit.RegisterCentralCommunication(centralCommActor));
+        _logger.LogInformation(
+            "SiteCallAuditActor singleton created and registered with CentralCommunicationActor");
 
         _logger.LogInformation("Central actors registered. CentralCommunicationActor created.");
     }