fix(twincat): TOD write bound, historian note, driver-level refused-write test (#306)

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

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/TwinCATReadWriteTests.cs

@@ -191,6 +191,35 @@ public sealed class TwinCATReadWriteTests
         results.Single().StatusCode.ShouldBe(TwinCATStatusMapper.BadNotWritable);
     }
 
+    /// <summary>A refused temporal write (#306) surfaces a status through WriteAsync, never an exception.</summary>
+    [Theory]
+    [InlineData(TwinCATDataType.TimeOfDay, 86_400_000d, TwinCATStatusMapper.BadOutOfRange)]
+    [InlineData(TwinCATDataType.Time, -1d, TwinCATStatusMapper.BadOutOfRange)]
+    [InlineData(TwinCATDataType.DateTime, "TimeSpan", TwinCATStatusMapper.BadTypeMismatch)]
+    public async Task Refused_temporal_write_surfaces_status_not_exception(
+        TwinCATDataType type, object value, uint expected)
+    {
+        var (drv, factory) = NewDriver(new TwinCATTagDefinition("T", "ads://5.23.91.23.1.1:851", "MAIN.T", type));
+        await drv.InitializeAsync("{}", CancellationToken.None);
+        factory.Customise = () => new ConvertingFake();
+        if (value is "TimeSpan") value = TimeSpan.FromSeconds(1);
+
+        var results = await drv.WriteAsync([new WriteRequest("T", value)], CancellationToken.None);
+
+        results.Single().StatusCode.ShouldBe(expected);
+    }
+
+    // Runs the production write conversion the fake otherwise skips.
+    private sealed class ConvertingFake : FakeTwinCATClient
+    {
+        public override Task<uint> WriteValueAsync(
+            string symbolPath, TwinCATDataType type, int? bitIndex, object? value, CancellationToken ct)
+        {
+            AdsTwinCATClient.ConvertForWrite(type, value);
+            return base.WriteValueAsync(symbolPath, type, bitIndex, value, ct);
+        }
+    }
+
     /// <summary>Verifies that write exceptions surface as BadCommunicationError status.</summary>
     [Fact]
     public async Task Write_exception_surfaces_BadCommunicationError()

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/TwinCATTemporalCodecTests.cs

@@ -53,6 +53,12 @@ public sealed class TwinCATTemporalCodecTests
     public void Time_encode_refuses_out_of_range(double value)
         => Should.Throw<OverflowException>(() => TwinCATTemporalCodec.Encode(TwinCATDataType.Time, value));
 
+    [Theory]
+    [InlineData(86_400_000d)]
+    [InlineData(-1d)]
+    public void Tod_encode_refuses_a_full_day_or_more(double value)
+        => Should.Throw<OverflowException>(() => TwinCATTemporalCodec.Encode(TwinCATDataType.TimeOfDay, value));
+
     [Fact]
     public void Dt_before_1970_is_refused()
         => Should.Throw<OverflowException>(() =>