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.Host/Actors/AkkaHostedService.cs

@@ -1009,6 +1009,18 @@ akka {{
         // direction one-way (Host knows both; Communication doesn't reach back
         // into AuditLog).
         grpcServer?.SetSiteAuditQueue(siteAuditQueue);
+        // Site Call Audit (#22): hand the site-local OperationTrackingStore to
+        // the gRPC server so the PullSiteCalls reconciliation RPC can serve
+        // central's self-heal pulls. siteTrackingStore is resolved above with
+        // GetService — present on site composition roots, null on central — so
+        // wire the seam only when the store exists. Like SetSiteAuditQueue, both
+        // the store and the gRPC server are singletons; wiring here keeps the
+        // dependency direction one-way (Host knows both; Communication doesn't
+        // reach back into SiteRuntime).
+        if (siteTrackingStore is not null)
+        {
+            grpcServer?.SetOperationTrackingStore(siteTrackingStore);
+        }
         grpcServer?.SetReady(_actorSystem!);
     }
 }