feat(inbound): routed Route.To().WaitForAttribute — contract + central path (spec §6)

src/ZB.MOM.WW.ScadaBridge.Communication/CommunicationService.cs

@@ -445,6 +445,25 @@ public class CommunicationService
             envelope, _options.IntegrationTimeout, cancellationToken);
     }
 
+    /// <summary>
+    /// Routes an inbound API wait-for-attribute request to a site (spec §6).
+    /// </summary>
+    /// <param name="siteId">The target site identifier.</param>
+    /// <param name="request">The wait-for-attribute route request.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>The wait-for-attribute route response.</returns>
+    public async Task<RouteToWaitForAttributeResponse> RouteToWaitForAttributeAsync(
+        string siteId, RouteToWaitForAttributeRequest request, CancellationToken cancellationToken = default)
+    {
+        var envelope = new SiteEnvelope(siteId, request);
+        // A wait legitimately blocks up to request.Timeout on the site, so the cluster
+        // Ask must be bounded by the WAIT deadline (plus integration-timeout slack for
+        // the round trip), not the generic IntegrationTimeout used by the other routes.
+        var askTimeout = request.Timeout + _options.IntegrationTimeout;
+        return await GetActor().Ask<RouteToWaitForAttributeResponse>(
+            envelope, askTimeout, cancellationToken);
+    }
+
     // ── Notification Outbox (central-local actor — Asked directly, no SiteEnvelope) ──
 
     /// <summary>