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>

tools/opcuacli-dotnet/Commands/WriteCommand.cs

@@ -0,0 +1,44 @@
+using CliFx;
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using Opc.Ua;
+using Opc.Ua.Client;
+
+namespace OpcUaCli.Commands;
+
+[Command("write", Description = "Write a value to a node")]
+public class WriteCommand : ICommand
+{
+    [CommandOption("url", 'u', Description = "OPC UA server endpoint URL", IsRequired = true)]
+    public string Url { get; init; } = default!;
+
+    [CommandOption("node", 'n', Description = "Node ID (e.g. ns=2;s=MyNode)", IsRequired = true)]
+    public string NodeId { get; init; } = default!;
+
+    [CommandOption("value", 'v', Description = "Value to write", IsRequired = true)]
+    public string Value { get; init; } = default!;
+
+    public async ValueTask ExecuteAsync(IConsole console)
+    {
+        using var session = await OpcUaHelper.ConnectAsync(Url);
+
+        var node = new NodeId(NodeId);
+        var current = await session.ReadValueAsync(node);
+        var typedValue = OpcUaHelper.ConvertValue(Value, current.Value);
+
+        var writeValue = new WriteValue
+        {
+            NodeId = node,
+            AttributeId = Attributes.Value,
+            Value = new DataValue(new Variant(typedValue))
+        };
+
+        var request = new WriteValueCollection { writeValue };
+        var response = await session.WriteAsync(null, request, CancellationToken.None);
+
+        if (StatusCode.IsGood(response.Results[0]))
+            await console.Output.WriteLineAsync($"Write successful: {NodeId} = {typedValue}");
+        else
+            await console.Output.WriteLineAsync($"Write failed: {response.Results[0]}");
+    }
+}