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>

src/ZB.MOM.WW.LmxOpcUa.Host/OpcUa/LmxNodeManager.cs

@@ -1100,6 +1100,11 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.OpcUa
             ///     Gets or sets the Galaxy tag reference for the acknowledge message that triggers acknowledgment.
             /// </summary>
             public string AckMsgTagReference { get; set; } = "";
+
+            /// <summary>
+            ///     Gets or sets the most recent acknowledged state so duplicate transitions are not reissued.
+            /// </summary>
+            public bool? LastAcked { get; set; }
         }
 
         #region Read/Write Handlers
@@ -1726,13 +1731,15 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.OpcUa
                                     alarmInfo = null;
                             }
 
-                            // Check for Acked transitions
+                            // Check for Acked transitions — skip if state hasn't changed
                             if (_alarmAckedTags.TryGetValue(address, out ackedAlarmInfo))
                             {
                                 newAcked = vtq.Value is true || vtq.Value is 1 ||
                                            (vtq.Value is int ackedIntVal && ackedIntVal != 0);
-                                pendingAckedEvents.Add((ackedAlarmInfo, newAcked));
-                                ackedAlarmInfo = null; // handled
+                                if (ackedAlarmInfo.LastAcked.HasValue && newAcked == ackedAlarmInfo.LastAcked.Value)
+                                    ackedAlarmInfo = null; // No transition → skip
+                                else
+                                    pendingAckedEvents.Add((ackedAlarmInfo, newAcked));
                             }
                         }
 
@@ -1818,6 +1825,12 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.OpcUa
                             // Apply Acked state changes
                             foreach (var (info, acked) in pendingAckedEvents)
                             {
+                                // Double-check dedup under lock
+                                if (info.LastAcked.HasValue && acked == info.LastAcked.Value)
+                                    continue;
+
+                                info.LastAcked = acked;
+
                                 var condition = info.ConditionNode;
                                 if (condition == null) continue;