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>

src/ZB.MOM.WW.LmxOpcUa.Client.Shared/Models/BrowseResult.cs

@@ -0,0 +1,35 @@
+namespace ZB.MOM.WW.LmxOpcUa.Client.Shared.Models;
+
+/// <summary>
+/// Represents a single node in the browse result set.
+/// </summary>
+public sealed class BrowseResult
+{
+    /// <summary>
+    /// The string representation of the node's NodeId.
+    /// </summary>
+    public string NodeId { get; }
+
+    /// <summary>
+    /// The display name of the node.
+    /// </summary>
+    public string DisplayName { get; }
+
+    /// <summary>
+    /// The node class (e.g., "Object", "Variable", "Method").
+    /// </summary>
+    public string NodeClass { get; }
+
+    /// <summary>
+    /// Whether the node has child references.
+    /// </summary>
+    public bool HasChildren { get; }
+
+    public BrowseResult(string nodeId, string displayName, string nodeClass, bool hasChildren)
+    {
+        NodeId = nodeId;
+        DisplayName = displayName;
+        NodeClass = nodeClass;
+        HasChildren = hasChildren;
+    }
+}