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

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorDbLessTests.cs

@@ -177,11 +177,13 @@ public sealed class DriverHostActorDbLessTests : RuntimeActorTestBase
     }
 
     /// <summary>
-    ///     Regression — a DB-backed actor (non-null <c>dbFactory</c>, no alarm store passed) still spawns
-    ///     the host on the EF-store fallback path, exactly as before Phase 4.
+    ///     Phase 4 Task 9 — the ConfigDb-backed EF fallback is retired. A DB-backed actor (non-null
+    ///     <c>dbFactory</c>) with no alarm store now SKIPS the ScriptedAlarm host: the wired
+    ///     <c>IAlarmStateStore</c> is the only source of condition-state persistence, and there is no
+    ///     longer an EF store constructed over <c>dbFactory</c>.
     /// </summary>
     [Fact]
-    public void DbBackedNode_WithNoStore_StillSpawnsScriptedAlarmHost_OnEfFallback()
+    public void DbBackedNode_WithNoStore_SkipsScriptedAlarmHost()
     {
         var publish = CreateTestProbe();
         var actor = Sys.ActorOf(DriverHostActor.Props(
@@ -192,7 +194,7 @@ public sealed class DriverHostActorDbLessTests : RuntimeActorTestBase
             alarmStateStore: null));
 
         AwaitStarted(actor);
-        ResolveChild(actor, "scripted-alarm-host").ShouldNotBeNull();
+        ResolveChild(actor, "scripted-alarm-host").ShouldBeNull();
     }
 
     /// <summary>