feat: 引擎多出口路由/退回/移交/或签补齐 + 定义 layout 坐标

- 多出口：FlwTask 增 edge_name 列（sql/20260916），FlwTaskRepository.claimAndFinish
  同步落列；FlowTaskService.handle 出度>1 时 edgeName 必填；FlowEngine.continueAdvance
  按 edge name 选路（单出口原路径逐字节兼容，未命中不推进）；FlowAdvanceService/
  FlowNodeAdvanceListener 透传；BranchScope 从 FlowEngine 提取
- DefValidator：多出口出口命名必填且同节点唯一；跨分支连线发布期明确拒绝
- 退回 POST /task/{id}/returnBack：默认退主管线最近已批节点，精确失效当前节点待办，
  split 幂等 upsert 使退回重走并行段不撞 flw_branch uk
- 移交 POST /task/{id}/transfer：TRANSFERRED(5)+新建待办，AssigneeResolver.requireUserName
- 或签 ANY 补齐：首个同意失效同节点兄弟待办
- 已办口径/撤回守卫：status in (1,2,4,5)；新事件 flow.returned/flow.transferred
- FlowDiagramService：EdgeVo.name/NodeVo.state/DiagramVo.layout，办件图状态计算
- 新 IT：多出口×3、ANY 或签、退回重走并行段、退回/移交/撤回

mvn test 84/84 绿

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

@@ -1,5 +1,7 @@
 package com.yunhai.flowcenter.service;
 
+import com.yunhai.flowcenter.engine.BranchScope;
+import com.yunhai.flowcenter.engine.FlowDefModel;
 import com.yunhai.flowcenter.engine.FlowEngine;
 import com.yunhai.flowcenter.entity.FlwBranch;
 import com.yunhai.flowcenter.entity.FlwDef;
@@ -111,6 +113,7 @@ public class FlowQueryService {
             row.put("handleTime", str(t.getHandleTime()));
             row.put("deadline", str(t.getDeadline()));
             row.put("urgeCount", t.getUrgeCount());
+            row.put("edgeName", t.getEdgeName());
             trace.add(row);
         }
         detail.setTrace(trace);
@@ -135,6 +138,53 @@ public class FlowQueryService {
         }
         FlwDef def = defRepository.findById(instance.getDefId()).orElse(null);
         detail.setNodeSummary(def == null ? "" : FlowEngine.nodeSummary(flowEngine.parseModel(def)));
+        // 办理面板数据（出口/退回目标/移交标记）：仅对持本人待办的查看者填充
+        FlwTask myPend = viewerId == null ? null : tasks.stream()
+                .filter(t -> viewerId.equals(t.getAssigneeId())
+                        && t.getStatus() == FlwEnums.TaskStatus.PENDING.getCode())
+                .findFirst().orElse(null);
+        if (myPend != null && def != null) {
+            FlowDefModel model = flowEngine.parseModel(def);
+            String curNodeId = myPend.getNodeId();
+            List<FlowDefModel.Edge> outs = model.outEdges(curNodeId);
+            if (outs.size() > 1) {
+                List<Map<String, Object>> outlets = new ArrayList<>();
+                for (FlowDefModel.Edge e : outs) {
+                    Map<String, Object> o = new HashMap<>();
+                    o.put("name", e.name);
+                    o.put("toNodeId", e.to);
+                    FlowDefModel.Node to = model.node(e.to);
+                    o.put("toNodeName", to == null ? e.to
+                            : (to.name == null || to.name.isEmpty() ? e.to : to.name));
+                    outlets.add(o);
+                }
+                detail.setOutlets(outlets);
+            } else {
+                detail.setOutlets(new ArrayList<>());
+            }
+            // 可退回目标：办件已办过的主线审批节点（去重，排除当前节点）
+            Map<String, Map<String, Object>> targets = new java.util.LinkedHashMap<>();
+            for (FlwTask t : tasks) {
+                if (t.getStatus() != FlwEnums.TaskStatus.APPROVED.getCode()
+                        || t.getNodeId().equals(myPend.getNodeId())
+                        || BranchScope.keyOf(model, t.getNodeId()) != null) {
+                    continue;
+                }
+                FlowDefModel.Node node = model.node(t.getNodeId());
+                if (node != null && FlowDefModel.TYPE_APPROVAL.equals(node.type)
+                        && !targets.containsKey(t.getNodeId())) {
+                    Map<String, Object> r = new HashMap<>();
+                    r.put("nodeId", node.id);
+                    r.put("nodeName", node.name == null || node.name.isEmpty() ? node.id : node.name);
+                    targets.put(node.id, r);
+                }
+            }
+            detail.setReturnTargets(new ArrayList<>(targets.values()));
+            detail.setCanTransfer(true);
+        } else {
+            detail.setOutlets(new ArrayList<>());
+            detail.setReturnTargets(new ArrayList<>());
+        }
         return detail;
     }