fix(mtconnect): review rulings for CONDITION alarms (#626)

- Unavailable keeps an ACTIVE condition active: quality-only BadNoCommunication; on data
  return same statement => quality-only Good, Normal => Clear, different => Retrigger.
- A changed alarm reference set (alarm-bearing delta = full rebuild) clears the whole
  last-told record so every active condition is re-asserted; the same set keeps it.
- Quality-only events go through the host's AlarmQualityUpdate path, never a projected
  snapshot (which could ack a retained unacked condition or rewrite message/severity).
- Deterministic tie-break between equal-level conditions (ordinal nativeCode, then type).
- Dedup key is level+nativeCode+nativeSeverity+qualifier; a text-only change updates nothing.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

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

@@ -273,7 +273,8 @@ public sealed class DriverHostActorNativeAlarmTests : RuntimeActorTestBase
 
     /// <summary>Gitea #626 — a QUALITY-ONLY native event (an <see cref="AlarmTransitionKind.Unspecified"/> kind
     /// carrying <see cref="AlarmEventArgs.QualityStatusCode"/>, e.g. an MTConnect condition gone Unavailable while
-    /// already Normal) re-annotates the condition's Quality through the ordinary state update, and publishes NO
+    /// already Normal) re-annotates the condition's Quality through the quality-only node path
+    /// (<see cref="OpcUaPublishActor.AlarmQualityUpdate"/> — NOT a projected snapshot), and publishes NO
     /// <c>alerts</c> row — it is not an alarm transition. The positive control is the Raise that follows: it
     /// MUST publish, and it must be the FIRST alerts message, so the absence is proven rather than timed.</summary>
     [Fact]
@@ -298,10 +299,10 @@ public sealed class DriverHostActorNativeAlarmTests : RuntimeActorTestBase
             Kind: AlarmTransitionKind.Unspecified,
             QualityStatusCode: OpcUaStatus.BadNoCommunication)));
 
-        var annotated = publish.ExpectMsg<OpcUaPublishActor.AlarmStateUpdate>(TimeSpan.FromSeconds(5));
+        var annotated = publish.ExpectMsg<OpcUaPublishActor.AlarmQualityUpdate>(TimeSpan.FromSeconds(5));
         annotated.AlarmNodeId.ShouldBe(AlarmRawPath);
-        annotated.State.Active.ShouldBeFalse();
-        annotated.State.StatusCode.ShouldBe(OpcUaStatus.BadNoCommunication);
+        annotated.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        annotated.StatusCode.ShouldBe(OpcUaStatus.BadNoCommunication);
 
         // Positive control: a real transition after it DOES publish, and is the first thing on the topic.
         actor.Tell(new DriverInstanceActor.AttributeAlarmPublished("drv-1", new AlarmEventArgs(
@@ -327,6 +328,46 @@ public sealed class DriverHostActorNativeAlarmTests : RuntimeActorTestBase
         evt.Severity.ShouldBe(800);
     }
 
+    /// <summary>Gitea #626 (review MINOR 1) — after a deploy (which clears the projector's prior state), a
+    /// quality-only event on a raised, UNACKNOWLEDGED condition must not reach the node as a snapshot: a projected
+    /// "keep the state" would default to inactive+acked, silently acknowledging it and rewriting its message and
+    /// severity. Only an <see cref="OpcUaPublishActor.AlarmQualityUpdate"/> (which writes Quality alone) may be
+    /// sent. Proven by order: the next message after it is the positive control's state update.</summary>
+    [Fact]
+    public void Quality_only_event_never_sends_a_state_snapshot_that_could_ack_or_rewrite()
+    {
+        var db = NewInMemoryDbFactory();
+        var deploymentId = SeedV3AlarmDeployment(db, RevA, Driver: "drv-1", Tag: "temp_hi");
+        var (actor, publish) = SpawnHostAndApply(db, deploymentId);
+
+        actor.Tell(new DriverInstanceActor.AttributeAlarmPublished("drv-1", new AlarmEventArgs(
+            new StubAlarmHandle(), "Temp", AlarmRawPath, "SYSTEM", "spindle fault", AlarmSeverity.High, Ts,
+            Kind: AlarmTransitionKind.Raise, OpcUaSeverity: 800, QualityStatusCode: OpcUaStatus.Good)));
+        publish.ExpectMsg<OpcUaPublishActor.AlarmStateUpdate>(TimeSpan.FromSeconds(5)).State.Acknowledged.ShouldBeFalse();
+
+        // Whatever the projector's prior state is (any apply clears it), a quality-only event must never be
+        // projected — the routing below is the whole guard, so no deploy needs staging here.
+
+        actor.Tell(new DriverInstanceActor.AttributeAlarmPublished("drv-1", new AlarmEventArgs(
+            new StubAlarmHandle(), "Temp", AlarmRawPath, "SYSTEM", "spindle fault", AlarmSeverity.High, Ts,
+            Kind: AlarmTransitionKind.Unspecified, OpcUaSeverity: 800,
+            QualityStatusCode: OpcUaStatus.BadNoCommunication)));
+        // Positive control.
+        actor.Tell(new DriverInstanceActor.AttributeAlarmPublished("drv-1", new AlarmEventArgs(
+            new StubAlarmHandle(), "Temp", AlarmRawPath, "SYSTEM", "control", AlarmSeverity.High, Ts,
+            Kind: AlarmTransitionKind.Retrigger, OpcUaSeverity: 800, QualityStatusCode: OpcUaStatus.Good)));
+
+        var next = publish.FishForMessage(
+            m => m is OpcUaPublishActor.AlarmQualityUpdate or OpcUaPublishActor.AlarmStateUpdate,
+            TimeSpan.FromSeconds(5));
+        next.ShouldBeOfType<OpcUaPublishActor.AlarmQualityUpdate>().StatusCode.ShouldBe(OpcUaStatus.BadNoCommunication);
+        var control = publish.FishForMessage(
+            m => m is OpcUaPublishActor.AlarmQualityUpdate or OpcUaPublishActor.AlarmStateUpdate,
+            TimeSpan.FromSeconds(5));
+        control.ShouldBeOfType<OpcUaPublishActor.AlarmStateUpdate>().State.Message.ShouldBe("control",
+            "the quality-only event must produce no state snapshot ahead of the control");
+    }
+
     /// <summary>#477 Layer 2 — a driver <see cref="DriverInstanceActor.ConnectivityChanged"/> annotates the
     /// Quality of the driver's native conditions via <see cref="OpcUaPublishActor.AlarmQualityUpdate"/>: comms
     /// lost → Bad, restored → Good, at the raw condition NodeId + realm. No alarm transition is involved — this