feat(mesh-phase4): DriverHostActor runs ConfigDb-free (LocalDb alarm store, guarded acks)

Nullable ConfigDb factory; UpsertNodeDeploymentState no-ops when absent
(central persists acks from the ApplyAck); scripted-alarm condition state
served from the LocalDb store instead of the ConfigDb-backed Ef store.
Combines Phase-4 Tasks 4 + 6. Removes the interim dbFactory! cast.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

src/Server/ZB.MOM.WW.OtOpcUa.Host/Configuration/LocalDbRegistration.cs

@@ -2,7 +2,9 @@ using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using ZB.MOM.WW.LocalDb;
 using ZB.MOM.WW.LocalDb.Replication;
+using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
 using ZB.MOM.WW.OtOpcUa.Runtime.DeploymentCache;
+using ZB.MOM.WW.OtOpcUa.Runtime.ScriptedAlarms;
 
 namespace ZB.MOM.WW.OtOpcUa.Host.Configuration;
 
@@ -96,6 +98,13 @@ public static class LocalDbRegistration
         // replicating, and never written to.
         services.AddSingleton<IDeploymentArtifactCache, LocalDbDeploymentArtifactCache>();
 
+        // Per-cluster mesh Phase 4: scripted-alarm condition state served from the replicated LocalDb
+        // store instead of the ConfigDb-backed EF store, so a driver-only node (no ConfigDb) keeps its
+        // Part 9 condition state and mirrors it to its pair peer. Driver-role only, alongside the cache —
+        // admin-only nodes never register LocalDb. WithOtOpcUaRuntimeActors resolves it optionally and
+        // threads it into DriverHostActor's ScriptedAlarm engine. Singleton to match ILocalDb + the cache.
+        services.AddSingleton<IAlarmStateStore, LocalDbAlarmConditionStateStore>();
+
         return services;
     }
 }