feat(commons): additive Trace flag + ChildExecutionId/TraceEvents on route/call/write/change records

Flow Debugger (design 2026-09-05 §5.2/§5.4): Trace rides beside ParentExecutionId on
RouteToCallRequest/RouteToSetAttributesRequest/ScriptCallRequest/SetStaticAttributeCommand/
AttributeValueChanged; RouteToCallResponse and ScriptCallResult carry the site run's
ExecutionId and its ScriptTrace AuditEvents inline. All trailing optional — zero call-site edits.

Claude-Session: https://claude.ai/code/session_01GSLkkHKz9JrAtmJjmQK3cP

src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Instance/SetStaticAttributeCommand.cs

@@ -19,13 +19,15 @@ namespace ZB.MOM.WW.ScadaBridge.Commons.Messages.Instance;
 /// <c>AttributeValueChanged</c> so an alarm the write trips can record it as the
 /// on-trigger script run's <c>ParentExecutionId</c>.
 /// </param>
+/// <param name="Trace">Flow Debugger trace flag — see design 2026-09-05 §5.2. Additive; defaults to untraced.</param>
 public record SetStaticAttributeCommand(
     string CorrelationId,
     string InstanceUniqueName,
     string AttributeName,
     string Value,
     DateTimeOffset Timestamp,
-    Guid? SourceExecutionId = null);
+    Guid? SourceExecutionId = null,
+    bool Trace = false);
 
 /// <summary>
 /// Response confirming that a static attribute was set.