worker(alarms): SyntheticAlarmGuid internal + alarmmgr-parity assertion (review fixes)

src/ZB.MOM.WW.MxGateway.Worker.Tests/MxAccess/AlarmDispatcherTests.cs

@@ -62,6 +62,8 @@ public sealed class AlarmDispatcherTests
         Assert.Equal("TestArea", body.Category);
         Assert.NotNull(body.TransitionTimestamp);
         Assert.Equal(ts, body.TransitionTimestamp.ToDateTime());
+        Assert.False(body.Degraded);
+        Assert.Equal(AlarmProviderMode.Alarmmgr, body.SourceProvider);
     }
 
     /// <summary>

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAlarmSnapshot.cs

@@ -6,6 +6,8 @@ namespace ZB.MOM.WW.MxGateway.Worker.MxAccess;
 ///     Single alarm record as emitted by the wnwrapConsumer XML stream.
 ///     Field names match the captured XML schema (see
 ///     <c>docs/AlarmClientDiscovery.md</c> "Option A — captured" section).
+///     Records are also produced by the subtag synthesis path when
+///     <see cref="Degraded"/> is set.
 /// </summary>
 public sealed class MxAlarmSnapshotRecord
 {

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/SyntheticAlarmGuid.cs

@@ -11,7 +11,7 @@ namespace ZB.MOM.WW.MxGateway.Worker.MxAccess;
 ///     repeated transitions for the same alarm reference correlate downstream
 ///     (acknowledge, snapshot, OPC UA mapping) without an alarmmgr-supplied GUID.
 /// </summary>
-public static class SyntheticAlarmGuid
+internal static class SyntheticAlarmGuid
 {
     /// <summary>
     ///     Produces a stable <see cref="Guid"/> for the given alarm reference.