feat(flow): 回调信封升级——事件携带操作人身份（operatorUserId/operatorName）

在飞工作合入：FlowEvent 增操作人字段（可空），引擎/推进监听/回调派发全程透传，
对齐 SDK FlowCallbackEvent 的 taskId/operator 字段（规范 §6.4）。

src/main/java/com/yunhai/flowcenter/service/FlowInstanceService.java

@@ -142,7 +142,8 @@ public class FlowInstanceService {
                 FlwEnums.TaskStatus.WITHDRAWN, instance.getSubmitterId(), instance.getSubmitterName());
         Map<String, Object> data = new HashMap<>();
         data.put("result", "WITHDRAWN");
-        eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.WITHDRAWN, instanceId, null, data));
+        eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.WITHDRAWN, instanceId, null,
+                instance.getSubmitterId(), instance.getSubmitterName(), data));
     }
 
     /**
@@ -230,7 +231,8 @@ public class FlowInstanceService {
         FlowDefModel model = flowEngine.parseModel(requireDef(instance.getDefId()));
         Map<String, Object> data = new HashMap<>();
         data.put("nodeSummary", FlowEngine.nodeSummary(model));
-        eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.SUBMITTED, instance.getId(), null, data));
+        eventPublisher.publishEvent(FlowEvent.of(FlowEvent.Type.SUBMITTED, instance.getId(), null,
+                instance.getSubmitterId(), instance.getSubmitterName(), data));
     }
 
     /** 代发起结果值对象 */