Add UI features, alarm ack, historian UTC fix, and Client.UI documentation

Major changes across the client stack:
- Settings persistence (connection, subscriptions, alarm source)
- Deferred OPC UA SDK init for instant startup
- Array/status code formatting, write value popup, alarm acknowledgment
- Severity-colored alarm rows, condition dedup on server side
- DateTimeRangePicker control with preset buttons and UTC text input
- Historian queries use wwTimezone=UTC and OPCQuality column
- Recursive subscribe from tree, multi-select remove
- Connection panel with expander, folder chooser for cert path
- Dynamic tab headers showing subscription/alarm counts
- Client.UI.md documentation with headless-rendered screenshots

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

tests/ZB.MOM.WW.LmxOpcUa.Client.Shared.Tests/Fakes/FakeSessionAdapter.cs

@@ -128,6 +128,12 @@ internal sealed class FakeSessionAdapter : ISessionAdapter
         return Task.FromResult<ISubscriptionAdapter>(sub);
     }
 
+    public Task<IList<object>?> CallMethodAsync(NodeId objectId, NodeId methodId, object[] inputArguments,
+        CancellationToken ct = default)
+    {
+        return Task.FromResult<IList<object>?>(null);
+    }
+
     public Task CloseAsync(CancellationToken ct)
     {
         Closed = true;