docs+test(closeout): final-review reservations — stale ACL prose, worker test gaps, config sample fix

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

@@ -330,6 +330,44 @@ public sealed class FailoverAlarmConsumerTests
         Assert.Equal(22, sut.AcknowledgeByName("a", "p", "g", "c", "n", "node", "dom", "full"));
     }
 
+    /// <summary>
+    ///     Proves that the snapshot truncation verdict is read from whichever child
+    ///     is currently active, not cached from the primary: a capped primary reports
+    ///     <see langword="true"/>, and after failover the standby's own verdict
+    ///     replaces it. The verdict drives the dashboard's completeness caveat, so a
+    ///     stale one would either keep a banner on screen for a feed that is now
+    ///     complete or, worse, clear it for one that is not.
+    /// </summary>
+    [Fact]
+    public void SnapshotActiveAlarms_TruncationVerdictComesFromActiveChild()
+    {
+        FlakyPrimary primary = new FlakyPrimary { ThrowOnPoll = false, SnapshotTruncated = true };
+        StubStandby standby = new StubStandby { SnapshotTruncated = false };
+        FailoverSettings settings = new FailoverSettings(threshold: 1, probeIntervalSeconds: 0, stableProbes: 1);
+        using FailoverAlarmConsumer sut = new FailoverAlarmConsumer(primary, standby, settings);
+
+        sut.Subscribe(@"\\HOST\Galaxy!Area");
+        Assert.Equal(AlarmProviderMode.Alarmmgr, sut.Mode);
+
+        // Active = Primary → the primary's capped fetch surfaces.
+        _ = sut.SnapshotActiveAlarms(out bool truncatedOnPrimary);
+        Assert.True(truncatedOnPrimary);
+
+        // Force a failover by failing the primary past threshold.
+        primary.ThrowOnPoll = true;
+        sut.PollOnce(); // threshold=1 → switch to Subtag
+        Assert.Equal(AlarmProviderMode.Subtag, sut.Mode);
+
+        // Active = Standby → its own verdict, not the primary's leftover true.
+        _ = sut.SnapshotActiveAlarms(out bool truncatedOnStandby);
+        Assert.False(truncatedOnStandby);
+
+        // And the standby really is the source: flip its verdict and the answer follows.
+        standby.SnapshotTruncated = true;
+        _ = sut.SnapshotActiveAlarms(out bool truncatedAfterStandbyCaps);
+        Assert.True(truncatedAfterStandbyCaps);
+    }
+
     /// <summary>
     ///     Proves that an intermittent failure during failback probing resets the
     ///     clean-probe counter to zero, requiring a fresh unbroken run of