fix(options): bind + validate OperationTrackingOptions; register the site IOperationTrackingStore that two comments claimed AddSiteRuntime provides (plan R2-08 T8, arch-review 08r2 NF4)

VERIFY-THEN-FIX: the plan-authoring discovery is CONFIRMED. No code anywhere in
src/ registered IOperationTrackingStore in DI, yet AkkaHostedService and
AuditLog SCE both comment that AddSiteRuntime provides it. Every consumer
resolved it via GetService (null-tolerant) and silently ran degraded:
cached-drain scheduler never armed, PullSiteCalls reconciliation seam never
wired, Tracking.Status degraded to audit-only. This is a FUNCTIONAL FIX riding
the hygiene plan: AddSiteRuntime now registers the store (site-only), so
site-local cached-call tracking runs in its intended mode. OperationTrackingOptions
is now bound + eagerly validated in the Host site-options block.

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

@@ -60,6 +60,19 @@ public static class ServiceCollectionExtensions
         });
         services.AddSingleton<ISiteStreamSubscriber>(sp => sp.GetRequiredService<SiteStreamManager>());
 
+        // Site-local cached-operation tracking store — the SQLite source of truth
+        // that Tracking.Status(TrackedOperationId) reads and the cached-call telemetry
+        // forwarder writes. Registered HERE (site-only) so the two comments that claim
+        // "the operational tracking store is registered by AddSiteRuntime" are true
+        // again (AuditLog SCE + AkkaHostedService). Before this (arch-review 08 round 2
+        // NF4/T8) it had no DI registration anywhere in src/, so every consumer resolved
+        // it as null and silently ran degraded (no cached-drain, no PullSiteCalls
+        // reconciliation, Tracking.Status audit-only). Central roots never call
+        // AddSiteRuntime, so this stays absent on central — matching the SITE-ONLY
+        // contract. OperationTrackingOptions is bound + validated by the Host's
+        // SiteServiceRegistration site-options block.
+        services.AddSingleton<Commons.Interfaces.IOperationTrackingStore, Tracking.OperationTrackingStore>();
+
         // Site-local repository implementations backed by SQLite
         services.AddScoped<IExternalSystemRepository, SiteExternalSystemRepository>();