Add cross-platform OPC UA client stack: shared library, CLI tool, and Avalonia UI

Implements Client.Shared (IOpcUaClientService with connection lifecycle, failover,
browse, read/write, subscriptions, alarms, history, redundancy), Client.CLI (8 CliFx
commands mirroring tools/opcuacli-dotnet), and Client.UI (Avalonia desktop app with
tree browser, read/write, subscriptions, alarms, and history tabs). All three target
.NET 10 and are covered by 249 unit tests.

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

tests/ZB.MOM.WW.LmxOpcUa.Client.CLI.Tests/NodeIdParserTests.cs

@@ -0,0 +1,87 @@
+using Opc.Ua;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.LmxOpcUa.Client.CLI.Helpers;
+
+namespace ZB.MOM.WW.LmxOpcUa.Client.CLI.Tests;
+
+public class NodeIdParserTests
+{
+    [Fact]
+    public void Parse_NullInput_ReturnsNull()
+    {
+        NodeIdParser.Parse(null).ShouldBeNull();
+    }
+
+    [Fact]
+    public void Parse_EmptyString_ReturnsNull()
+    {
+        NodeIdParser.Parse("").ShouldBeNull();
+    }
+
+    [Fact]
+    public void Parse_WhitespaceOnly_ReturnsNull()
+    {
+        NodeIdParser.Parse("   ").ShouldBeNull();
+    }
+
+    [Fact]
+    public void Parse_StandardStringFormat_ReturnsNodeId()
+    {
+        var result = NodeIdParser.Parse("ns=2;s=MyNode");
+        result.ShouldNotBeNull();
+        result.NamespaceIndex.ShouldBe((ushort)2);
+        result.Identifier.ShouldBe("MyNode");
+    }
+
+    [Fact]
+    public void Parse_NumericFormat_ReturnsNodeId()
+    {
+        var result = NodeIdParser.Parse("i=85");
+        result.ShouldNotBeNull();
+        result.IdType.ShouldBe(IdType.Numeric);
+    }
+
+    [Fact]
+    public void Parse_BareNumeric_ReturnsNamespace0NumericNodeId()
+    {
+        var result = NodeIdParser.Parse("85");
+        result.ShouldNotBeNull();
+        result.NamespaceIndex.ShouldBe((ushort)0);
+        result.Identifier.ShouldBe((uint)85);
+    }
+
+    [Fact]
+    public void Parse_WithWhitespacePadding_Trims()
+    {
+        var result = NodeIdParser.Parse("  ns=2;s=MyNode  ");
+        result.ShouldNotBeNull();
+        result.Identifier.ShouldBe("MyNode");
+    }
+
+    [Fact]
+    public void Parse_InvalidFormat_ThrowsFormatException()
+    {
+        Should.Throw<FormatException>(() => NodeIdParser.Parse("not-a-node-id"));
+    }
+
+    [Fact]
+    public void ParseRequired_NullInput_ThrowsArgumentException()
+    {
+        Should.Throw<ArgumentException>(() => NodeIdParser.ParseRequired(null));
+    }
+
+    [Fact]
+    public void ParseRequired_EmptyInput_ThrowsArgumentException()
+    {
+        Should.Throw<ArgumentException>(() => NodeIdParser.ParseRequired(""));
+    }
+
+    [Fact]
+    public void ParseRequired_ValidInput_ReturnsNodeId()
+    {
+        var result = NodeIdParser.ParseRequired("ns=2;s=TestNode");
+        result.ShouldNotBeNull();
+        result.Identifier.ShouldBe("TestNode");
+    }
+}