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.CLI.Tests/Fakes/FakeOpcUaClientService.cs

@@ -142,6 +142,12 @@ public sealed class FakeOpcUaClientService : IOpcUaClientService
         return Task.CompletedTask;
     }
 
+    public Task<StatusCode> AcknowledgeAlarmAsync(string conditionNodeId, byte[] eventId, string comment,
+        CancellationToken ct = default)
+    {
+        return Task.FromResult(new StatusCode(StatusCodes.Good));
+    }
+
     public Task<IReadOnlyList<DataValue>> HistoryReadRawAsync(
         NodeId nodeId, DateTime startTime, DateTime endTime, int maxValues = 1000, CancellationToken ct = default)
     {