test(opcua): package cross-platform lifecycle memory controls

scripts/validation/opcua-lifecycle-memory/EventPipeCapture.cs

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+// Read-only temporary diagnostic attachment. Requires Microsoft.Diagnostics.NETCore.Client from dotnet-trace.
+using System.Diagnostics.Tracing;
+using Microsoft.Diagnostics.NETCore.Client;
+
+var seconds = int.Parse(args[1]);
+if (seconds < 1 || seconds > 300) throw new ArgumentOutOfRangeException(nameof(seconds), "Use a bounded 1..300 second diagnostic attachment");
+var client = new DiagnosticsClient(int.Parse(args[0]));
+var providers = new[] { new EventPipeProvider("Microsoft-Windows-DotNETRuntime", EventLevel.Verbose, 0x18) };
+// Match the recorded experiment's API default (256 MiB capacity, not measured resident allocation).
+using var session = client.StartEventPipeSession(providers, requestRundown: false, circularBufferMB: 256);
+await using var file = File.Create(args[2]);
+var copy = session.EventStream.CopyToAsync(file);
+await Task.Delay(TimeSpan.FromSeconds(seconds));
+session.Stop();
+await copy;