Implement LmxOpcUa server — all 6 phases complete

Full OPC UA server on .NET Framework 4.8 (x86) exposing AVEVA System
Platform Galaxy tags via MXAccess. Mirrors Galaxy object hierarchy as
OPC UA address space, translating contained-name browse paths to
tag-name runtime references.

Components implemented:
- Configuration: AppConfiguration with 4 sections, validator
- Domain: ConnectionState, Quality, Vtq, MxDataTypeMapper, error codes
- MxAccess: StaComThread, MxAccessClient (partial classes), MxProxyAdapter
  using strongly-typed ArchestrA.MxAccess COM interop
- Galaxy Repository: SQL queries (hierarchy, attributes, change detection),
  ChangeDetectionService with auto-rebuild on deploy
- OPC UA Server: LmxNodeManager (CustomNodeManager2), LmxOpcUaServer,
  OpcUaServerHost with programmatic config, SecurityPolicy None
- Status Dashboard: HTTP server with HTML/JSON/health endpoints
- Integration: Full 14-step startup, graceful shutdown, component wiring

175 tests (174 unit + 1 integration), all passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/ZB.MOM.WW.LmxOpcUa.Tests/OpcUa/DataValueConverterTests.cs

@@ -0,0 +1,122 @@
+using System;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.LmxOpcUa.Host.Domain;
+using ZB.MOM.WW.LmxOpcUa.Host.OpcUa;
+
+namespace ZB.MOM.WW.LmxOpcUa.Tests.OpcUa
+{
+    public class DataValueConverterTests
+    {
+        [Fact]
+        public void FromVtq_Boolean()
+        {
+            var vtq = Vtq.Good(true);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(true);
+            Opc.Ua.StatusCode.IsGood(dv.StatusCode).ShouldBe(true);
+        }
+
+        [Fact]
+        public void FromVtq_Int32()
+        {
+            var vtq = Vtq.Good(42);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(42);
+        }
+
+        [Fact]
+        public void FromVtq_Float()
+        {
+            var vtq = Vtq.Good(3.14f);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(3.14f);
+        }
+
+        [Fact]
+        public void FromVtq_Double()
+        {
+            var vtq = Vtq.Good(3.14159);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(3.14159);
+        }
+
+        [Fact]
+        public void FromVtq_String()
+        {
+            var vtq = Vtq.Good("hello");
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe("hello");
+        }
+
+        [Fact]
+        public void FromVtq_DateTime_IsUtc()
+        {
+            var utcTime = new DateTime(2024, 6, 15, 10, 30, 0, DateTimeKind.Utc);
+            var vtq = new Vtq(utcTime, utcTime, Quality.Good);
+            var dv = DataValueConverter.FromVtq(vtq);
+            ((DateTime)dv.Value).Kind.ShouldBe(DateTimeKind.Utc);
+        }
+
+        [Fact]
+        public void FromVtq_TimeSpan_ConvertedToSeconds()
+        {
+            var vtq = Vtq.Good(TimeSpan.FromMinutes(2.5));
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(150.0);
+        }
+
+        [Fact]
+        public void FromVtq_StringArray()
+        {
+            var arr = new[] { "a", "b", "c" };
+            var vtq = Vtq.Good(arr);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(arr);
+        }
+
+        [Fact]
+        public void FromVtq_IntArray()
+        {
+            var arr = new[] { 1, 2, 3 };
+            var vtq = Vtq.Good(arr);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBe(arr);
+        }
+
+        [Fact]
+        public void FromVtq_BadQuality_MapsToStatusCode()
+        {
+            var vtq = Vtq.Bad(Quality.BadCommFailure);
+            var dv = DataValueConverter.FromVtq(vtq);
+            Opc.Ua.StatusCode.IsBad(dv.StatusCode).ShouldBe(true);
+        }
+
+        [Fact]
+        public void FromVtq_UncertainQuality()
+        {
+            var vtq = Vtq.Uncertain(42);
+            var dv = DataValueConverter.FromVtq(vtq);
+            Opc.Ua.StatusCode.IsUncertain(dv.StatusCode).ShouldBe(true);
+        }
+
+        [Fact]
+        public void FromVtq_NullValue()
+        {
+            var vtq = Vtq.Good(null);
+            var dv = DataValueConverter.FromVtq(vtq);
+            dv.Value.ShouldBeNull();
+        }
+
+        [Fact]
+        public void ToVtq_RoundTrip()
+        {
+            var original = new Vtq(42, DateTime.UtcNow, Quality.Good);
+            var dv = DataValueConverter.FromVtq(original);
+            var roundTrip = DataValueConverter.ToVtq(dv);
+
+            roundTrip.Value.ShouldBe(42);
+            roundTrip.Quality.ShouldBe(Quality.Good);
+        }
+    }
+}