feat(sitecallaudit): PullSiteCalls reconciliation plumbing (store read + RPC + site handler + central client)

Site Call Audit (#22): build the documented periodic reconciliation PULL
self-heal path for the eventually-consistent central SiteCalls mirror, as a
dedicated PullSiteCalls gRPC RPC kept separate from the audit pull. This is the
pull PLUMBING only; the central reconciliation tick is a separate follow-up.

- IOperationTrackingStore.ReadChangedSinceAsync(sinceUtc, batchSize): inclusive
  UpdatedAtUtc cursor, oldest-first, batch-capped; SQLite impl projects tracking
  rows onto SiteCallOperational (Kind->Channel, TargetSummary->Target, SourceSite
  left empty - the store has no site-id column).
- sitestream.proto: rpc PullSiteCalls + PullSiteCallsRequest/Response, mirroring
  PullAuditEvents; regenerated checked-in SiteStreamGrpc/*.cs.
- SiteCallDtoMapper.ToDto(SiteCallOperational): inverse of FromDto for the handler.
- SiteStreamGrpcServer.PullSiteCalls handler + SetOperationTrackingStore seam;
  Host wires the seam alongside SetSiteAuditQueue (site roles only).
- Central IPullSiteCallsClient + GrpcPullSiteCallsClient (home: AuditLog/Central to
  reuse ISiteEnumerator; SiteCallAudit does not reference AuditLog). Re-stamps
  SourceSite from the dialed siteId; no-throw on tolerable transport faults;
  SpecifyKind (not ToUniversalTime) cursor handling. Central-only DI registration.

Tests: ReadChangedSinceAsync (4), PullSiteCalls handler (6), GrpcPullSiteCallsClient
(8). Full solution build 0 warnings/0 errors (TreatWarningsAsErrors).

src/ZB.MOM.WW.ScadaBridge.AuditLog/ServiceCollectionExtensions.cs

@@ -473,6 +473,31 @@ public static class ServiceCollectionExtensions
             sp.GetRequiredService<GrpcPullAuditEventsClient.IPullAuditEventsInvoker>(),
             sp.GetRequiredService<ILogger<GrpcPullAuditEventsClient>>()));
 
+        // Site Call Audit (#22) reconciliation pull client — central-only, the
+        // sibling of the audit pull client above. Lives here (not in the
+        // SiteCallAudit project) so it can reuse the central-only
+        // ISiteEnumerator registered just above; SiteCallAudit does not
+        // reference AuditLog. The invoker owns the per-endpoint GrpcChannel
+        // cache, so it must be a singleton (a fresh invoker per resolution
+        // would leak channels). CommunicationOptions flow through when bound by
+        // the central Host, else defaults — mirrors the audit invoker.
+        services.TryAddSingleton<GrpcPullSiteCallsInvoker>(sp =>
+        {
+            var options = sp
+                .GetService<Microsoft.Extensions.Options.IOptions<
+                    ZB.MOM.WW.ScadaBridge.Communication.CommunicationOptions>>();
+            return options is null
+                ? new GrpcPullSiteCallsInvoker()
+                : new GrpcPullSiteCallsInvoker(options.Value);
+        });
+        services.TryAddSingleton<GrpcPullSiteCallsClient.IPullSiteCallsInvoker>(
+            sp => sp.GetRequiredService<GrpcPullSiteCallsInvoker>());
+
+        services.TryAddSingleton<IPullSiteCallsClient>(sp => new GrpcPullSiteCallsClient(
+            sp.GetRequiredService<ISiteEnumerator>(),
+            sp.GetRequiredService<GrpcPullSiteCallsClient.IPullSiteCallsInvoker>(),
+            sp.GetRequiredService<ILogger<GrpcPullSiteCallsClient>>()));
+
         return services;
     }
 }