fix(alarms): native-alarm re-statements no longer duplicate history or hide acked alarms (#656)

- AlarmTransitionKind.ActiveAcknowledged (appended): active AND acked applied as ONE projection.
  Galaxy ActiveAcked snapshot entries and OpcUaClient inactive->(active,acked) use it; the
  projector writes 'Activated' only if not already active, 'Acknowledged' only if not acked.
- AlarmEventArgs.IsRestatement (optional, default false): set only by Galaxy snapshot entries
  and OpcUaClient first sight. A flagged Retrigger on an Active+unacked condition with the same
  message and severity, or a flagged Clear on an inactive condition, writes no /alerts row.
- NativeAlarmProjector reports the history rows per transition; ForwardNativeAlarm writes one
  row per entry. Unflagged sources (FOCAS/MTConnect/AbCip, live Galaxy) are unchanged.
- Tests: projector rules each with a must-write control; OpcUaClient transition table;
  Galaxy feed/driver mapping; Galaxy + OpcUaClient end-to-end through DriverHostActor.

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

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmEventArgsExtensionTests.cs

@@ -84,6 +84,45 @@ public sealed class GalaxyDriverAlarmEventArgsExtensionTests
         observed[0].AlarmCategory.ShouldBeNull();
     }
 
+    /// <summary>
+    ///     Gitea #656 — a snapshot ActiveAcknowledged transition reaches <see cref="AlarmEventArgs"/> as
+    ///     <see cref="AlarmTransitionKind.ActiveAcknowledged"/> (not Unspecified, which would keep the host's prior
+    ///     state) with <see cref="AlarmEventArgs.IsRestatement"/> carried through; an unflagged transition stays false.
+    /// </summary>
+    [Fact]
+    public async Task ActiveAcknowledged_snapshot_transition_maps_kind_and_restatement_flag()
+    {
+        var feed = new FakeAlarmFeed();
+        using var driver = NewDriver(feed);
+
+        await driver.SubscribeAlarmsAsync(["Tank01"], CancellationToken.None);
+        var observed = new List<AlarmEventArgs>();
+        driver.OnAlarmEvent += (_, args) => observed.Add(args);
+
+        var t = new GalaxyAlarmTransition(
+            AlarmFullReference: "Tank01.Level.HiHi",
+            SourceObjectReference: "Tank01",
+            AlarmTypeName: "AnalogLimitAlarm.HiHi",
+            TransitionKind: GalaxyAlarmTransitionKind.ActiveAcknowledged,
+            SeverityBucket: AlarmSeverity.Critical,
+            OpcUaSeverity: 800,
+            RawMxAccessSeverity: 750,
+            OriginalRaiseTimestampUtc: null,
+            TransitionTimestampUtc: DateTime.UtcNow,
+            OperatorUser: "alice",
+            OperatorComment: "seen",
+            Category: "Process",
+            Description: "Tank 01 high-high level",
+            IsRestatement: true);
+        feed.Emit(t);
+        feed.Emit(t with { TransitionKind = GalaxyAlarmTransitionKind.Retrigger, IsRestatement = false });
+
+        observed.Select(e => (e.Kind, e.IsRestatement)).ShouldBe([
+            (AlarmTransitionKind.ActiveAcknowledged, true),
+            (AlarmTransitionKind.Retrigger, false),
+        ]);
+    }
+
     private static GalaxyDriver NewDriver(IGalaxyAlarmFeed feed)
     {
         var options = new GalaxyDriverOptions(