fix(opcuaclient): #649 review minors - CodeBits match, Bad-only exception ctor, BadNoData + Raw-resume tests, latent-impact docs

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

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests/OpcUaClientDriverHistoryWireTests.cs

@@ -17,6 +17,7 @@ public sealed class OpcUaClientDriverHistoryWireTests
     private const string HistRef = "Sim/dev1/Hist";
     private const string HistTag = "Plant.Hist.Series";
     private const uint Uncertain = 0x40000000u;
+    private const uint BadNoData = 0x809B0000u;
     private const uint BadUserAccessDenied = 0x801F0000u;
     private const uint BadHistoryOperationUnsupported = 0x80720000u;
 
@@ -55,6 +56,9 @@ public sealed class OpcUaClientDriverHistoryWireTests
             // Minimum stands in for "the backend refuses with some OTHER Bad status" (#649).
             if (aggregate == HistoryAggregateType.Minimum)
                 throw new HistoryReadStatusException(BadUserAccessDenied);
+            // Maximum stands in for a node-level BadNoData ("nothing in the window"), which must stay empty.
+            if (aggregate == HistoryAggregateType.Maximum)
+                throw new HistoryReadStatusException(BadNoData);
             if (aggregate != HistoryAggregateType.Average)
                 throw new HistoryAggregateNotSupportedException(aggregate);
 
@@ -204,6 +208,21 @@ public sealed class OpcUaClientDriverHistoryWireTests
         lock (fake.Calls) fake.Calls.ShouldContain($"processed:{HistTag}:Minimum");
     }
 
+    [Fact]
+    public async Task A_node_level_BadNoData_stays_an_empty_result_not_an_error()
+    {
+        var ct = TestContext.Current.CancellationToken;
+        var (rig, fake, drv) = await StartAsync("hist-badnodata", ct);
+        await using var _r = rig;
+        await using var _d = drv;
+
+        var result = await drv.ReadProcessedAsync(
+            HistRef, At(0), At(6), TimeSpan.FromSeconds(2), HistoryAggregateType.Maximum, ct);
+
+        result.Samples.ShouldBeEmpty();
+        lock (fake.Calls) fake.Calls.ShouldContain($"processed:{HistTag}:Maximum", "the call must have reached the backend");
+    }
+
     [Fact]
     public async Task A_Good_read_with_no_samples_in_the_window_is_still_empty_data_not_an_error()
     {