fix(historian): respect gateway ceilings and history value contracts

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadEventsTests.cs

@@ -295,12 +295,14 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
     /// HistoryRead call. The fake source MUST be invoked (proving we reached the bridge) and threw;
     /// the production catch now sets BOTH errors and results explicitly, so both are asserted here
     /// rather than relying on the SDK base pre-seeding results[i].</summary>
-    [Fact]
-    public async Task Events_backend_throw_yields_bad_status_and_does_not_escape()
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public async Task Events_backend_throw_yields_bad_status_and_does_not_escape(bool communication)
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        var fake = new RecordingHistorianDataSource { ThrowOnRead = true };
+        var fake = new RecordingHistorianDataSource { ThrowOnRead = !communication, ReadException = communication ? new System.IO.IOException("lost connection") : null };
         nm.HistorianDataSource = fake;
 
         const string equipmentId = "eq-boom";
@@ -321,10 +323,10 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
 
         // Authoritative per-node signal: errors[0] must be Bad.
         ServiceResult.IsBad(errors[0]).ShouldBeTrue();
-        errors[0].StatusCode.Code.ShouldBe(StatusCodes.BadHistoryOperationUnsupported);
+        errors[0].StatusCode.Code.ShouldBe(communication ? StatusCodes.BadNoCommunication : StatusCodes.BadHistoryOperationUnsupported);
         // The production catch now sets results[0] explicitly — assert it directly (not relying on base seeding).
         results[0].ShouldNotBeNull();
-        results[0].StatusCode.Code.ShouldBe(StatusCodes.BadHistoryOperationUnsupported);
+        results[0].StatusCode.Code.ShouldBe(communication ? StatusCodes.BadNoCommunication : StatusCodes.BadHistoryOperationUnsupported);
         // The source WAS entered (proving the override reached the bridge and the throw was swallowed).
         fake.EventsEntered.ShouldBeTrue();
         // ThrowOnRead fires before EventsCalled/LastSourceName are set — that's the throw path.
@@ -380,6 +382,7 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
     private sealed class RecordingHistorianDataSource : IHistorianDataSource
     {
         public bool ThrowOnRead { get; init; }
+        public Exception? ReadException { get; init; }
         public HistoricalEventsResult EventsResult { get; set; } =
             new(Array.Empty<HistoricalEvent>(), null);
 
@@ -411,6 +414,7 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
             CancellationToken cancellationToken)
         {
             EventsEntered = true;
+            if (ReadException is not null) throw ReadException;
             if (ThrowOnRead) throw new InvalidOperationException("backend boom for events");
             EventsCalled = true;
             LastSourceName = sourceName;