fix(client-cli): resolve Medium code-review findings (Client.CLI-001, Client.CLI-005)

Client.CLI-001: parse --start/--end with CultureInfo.InvariantCulture and
DateTimeStyles.AssumeUniversal|AdjustToUniversal so dates are culture-stable.
Client.CLI-005: SDK notification callbacks now hand off to an unbounded
channel drained on the main thread; handlers are unsubscribed before the
summary phase so no notification interleaves with console output.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Client/ZB.MOM.WW.OtOpcUa.Client.CLI/Commands/HistoryReadCommand.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using CliFx.Attributes;
 using CliFx.Infrastructure;
 using Opc.Ua;
@@ -27,13 +28,13 @@ public class HistoryReadCommand : CommandBase
     /// <summary>
     /// Gets the optional history start time string supplied by the operator.
     /// </summary>
-    [CommandOption("start", Description = "Start time (ISO 8601 or date string, default: 24 hours ago)")]
+    [CommandOption("start", Description = "Start time in ISO 8601 UTC format, e.g. 2026-01-15T08:00:00Z (default: 24 hours ago)")]
     public string? StartTime { get; init; }
 
     /// <summary>
     /// Gets the optional history end time string supplied by the operator.
     /// </summary>
-    [CommandOption("end", Description = "End time (ISO 8601 or date string, default: now)")]
+    [CommandOption("end", Description = "End time in ISO 8601 UTC format, e.g. 2026-01-15T09:00:00Z (default: now)")]
     public string? EndTime { get; init; }
 
     /// <summary>
@@ -70,10 +71,12 @@ public class HistoryReadCommand : CommandBase
             var nodeId = NodeIdParser.ParseRequired(NodeId);
             var start = string.IsNullOrEmpty(StartTime)
                 ? DateTime.UtcNow.AddHours(-24)
-                : DateTime.Parse(StartTime).ToUniversalTime();
+                : DateTime.Parse(StartTime, CultureInfo.InvariantCulture,
+                    DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
             var end = string.IsNullOrEmpty(EndTime)
                 ? DateTime.UtcNow
-                : DateTime.Parse(EndTime).ToUniversalTime();
+                : DateTime.Parse(EndTime, CultureInfo.InvariantCulture,
+                    DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
 
             IReadOnlyList<DataValue> values;