refactor(mesh-phase4): retire EfAlarmConditionStateStore + drop dead ScriptedAlarmState table (Task 9)

Scripted-alarm condition state lives in LocalDb (Phase 4); the ConfigDb-backed
Ef store + ScriptedAlarmState table are now dead. Removes the test-harness Ef
fallback (a DB-backed node with no store now skips the alarm host), deletes the
store + entity + model config, and drops the table via migration.

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

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ServiceCollectionExtensions.cs

@@ -286,8 +286,7 @@ public static class ServiceCollectionExtensions
             // Per-cluster mesh Phase 4: scripted-alarm condition-state store. Registered by the Host's
             // AddOtOpcUaLocalDb on driver-role nodes (the replicated LocalDb store), so condition state
             // persists with no ConfigDb; null elsewhere (admin-only graphs, test harnesses) → the actor
-            // falls back to an EfAlarmConditionStateStore over dbFactory, or skips the alarm host when
-            // there is no ConfigDb either.
+            // skips spawning the alarm host (the ConfigDb-backed EF fallback was retired in Phase 4 Task 9).
             var alarmStateStore = resolver.GetService<IAlarmStateStore>();
             // Per-cluster mesh Phase 3: ConfigSource:Mode selects where this driver reads config.
             // FetchAndCache pulls the artifact from central over gRPC and reads only the LocalDb cache;
@@ -473,7 +472,8 @@ public static class ServiceCollectionExtensions
                 // gated on hasAdmin and driver-only nodes are forced to FetchAndCache. DriverHostActor
                 // guards every ConfigDb-touching path on it (UpsertNodeDeploymentState no-ops; central
                 // persists acks from the ApplyAck) and serves scripted-alarm state from the LocalDb
-                // alarmStateStore instead of an EfAlarmConditionStateStore.
+                // alarmStateStore (there is no ConfigDb-backed EF fallback; the host skips the alarm
+                // host when no store was wired).
                 DriverHostActor.Props(dbFactory, roleInfo.LocalNode,
                     ackRouter: useClusterClient ? nodeComm : null,
                     driverFactory: driverFactory, localRoles: roleInfo.LocalRoles,