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/test/java/com/yunhai/flowcenter/engine/FlowEngineIT.java

@@ -243,6 +243,131 @@ class FlowEngineIT extends FlowTestSupport {
         assertEquals(2, taskRepository.findByInstanceIdOrderByIdAsc(outcome.getInstanceId()).size());
     }
 
+    @Test
+    void multiOutlet_approveWithChosenEdge_routesToTarget() {
+        mapDept("km", 101, "甲");
+        mapDept("kf", 102, "乙");
+        FlwDef def = saveAndPublishDef("t10", "多出口", multiOutletDef("km", "kf"));
+        FlowInstanceService.ApplyOutcome outcome = apply(def.getFlowGuid(), "biz-10", 201, "张三");
+        Long instanceId = outcome.getInstanceId();
+        FlwTask task = taskRepository.findByInstanceIdAndStatus(instanceId, 0).get(0);
+        // 选"通过"出口 → 直达 END 完成
+        taskService.handle(SCH, task.getId(), true, "ok", 101, "通过");
+        assertEquals(FlwEnums.InstanceStatus.COMPLETED.getCode(),
+                instanceRepository.findById(instanceId).get().getStatus());
+        assertEquals("通过", taskRepository.findById(task.getId()).get().getEdgeName());
+    }
+
+    @Test
+    void multiOutlet_chooseOtherEdge_routesToSecondNode() throws Exception {
+        mapDept("km", 101, "甲");
+        mapDept("kf", 102, "乙");
+        FlwDef def = saveAndPublishDef("t11", "多出口转向", multiOutletDef("km", "kf"));
+        FlowInstanceService.ApplyOutcome outcome = apply(def.getFlowGuid(), "biz-11", 201, "张三");
+        Long instanceId = outcome.getInstanceId();
+        FlwTask task = taskRepository.findByInstanceIdAndStatus(instanceId, 0).get(0);
+        // 选"转乙科"出口 → 到 n2 建新待办
+        taskService.handle(SCH, task.getId(), true, "转给乙科", 101, "转乙科");
+        assertEquals(FlwEnums.InstanceStatus.APPROVING.getCode(),
+                instanceRepository.findById(instanceId).get().getStatus());
+        List<FlwTask> pending = taskRepository.findByInstanceIdAndStatus(instanceId, 0);
+        assertEquals(1, pending.size());
+        assertEquals("n2", pending.get(0).getNodeId());
+        assertEquals(102, pending.get(0).getAssigneeId());
+        // 乙科通过 → 完成
+        taskService.handle(SCH, pending.get(0).getId(), true, "ok", 102);
+        assertEquals(FlwEnums.InstanceStatus.COMPLETED.getCode(),
+                instanceRepository.findById(instanceId).get().getStatus());
+    }
+
+    @Test
+    void multiOutlet_multiOutletNode_requiresEdgeName() {
+        mapDept("km", 101, "甲");
+        mapDept("kf", 102, "乙");
+        FlwDef def = saveAndPublishDef("t12", "多出口必选", multiOutletDef("km", "kf"));
+        FlowInstanceService.ApplyOutcome outcome = apply(def.getFlowGuid(), "biz-12", 201, "张三");
+        FlwTask task = taskRepository.findByInstanceIdAndStatus(outcome.getInstanceId(), 0).get(0);
+        assertThrows(BizException.class,
+                () -> taskService.handle(SCH, task.getId(), true, "ok", 101, null));
+        assertThrows(BizException.class,
+                () -> taskService.handle(SCH, task.getId(), true, "ok", 101, "不存在的出口"));
+    }
+
+    @Test
+    void anyCountersign_firstApprove_invalidatesSiblings_thenAdvances() {
+        mapDept("ky", 101, "甲");
+        mapDept("ky", 102, "乙");
+        FlwDef def = saveAndPublishDef("t13", "或签", anyCountersignDef("ky"));
+        FlowInstanceService.ApplyOutcome outcome = apply(def.getFlowGuid(), "biz-13", 201, "张三");
+        Long instanceId = outcome.getInstanceId();
+        List<FlwTask> pending = taskRepository.findByInstanceIdAndStatus(instanceId, 0);
+        assertEquals(2, pending.size());
+        // 或签：任一人同意即放行，兄弟待办失效（修复前行为=卡到全员办完）
+        taskService.handle(SCH, pending.get(0).getId(), true, "我先批", 101);
+        FlwInstance instance = instanceRepository.findById(instanceId).get();
+        assertEquals(FlwEnums.InstanceStatus.COMPLETED.getCode(), instance.getStatus());
+        List<FlwTask> all = taskRepository.findByInstanceIdOrderByIdAsc(instanceId);
+        assertEquals(FlwEnums.TaskStatus.APPROVED.getCode(), all.get(0).getStatus());
+        assertEquals(FlwEnums.TaskStatus.INVALIDATED.getCode(), all.get(1).getStatus());
+    }
+
+    @Test
+    void returnBack_fromTailNode_backToHead_thenReTraverseParallel_noUkViolation() {
+        mapDept("km", 103, "主");
+        mapDept("ka", 101, "甲");
+        mapDept("kb", 102, "乙");
+        FlwDef def = saveAndPublishDef("t14", "退回重入", mainlineParallelTailDef("km", "km"));
+        FlowInstanceService.ApplyOutcome outcome = apply(def.getFlowGuid(), "biz-14", 201, "张三");
+        Long instanceId = outcome.getInstanceId();
+        // 顺序推进：n1 → 并行双分支 → join → n3（在出口复核节点）
+        taskService.handle(SCH, tasksOf(instanceId, 103).get(0).getId(), true, "ok", 103);
+        taskService.handle(SCH, tasksOf(instanceId, 101).get(0).getId(), true, "ok", 101);
+        taskService.handle(SCH, tasksOf(instanceId, 102).get(0).getId(), true, "ok", 102);
+        FlwTask tail = tasksOf(instanceId, 103).get(0);
+        assertEquals("n3", tail.getNodeId());
+        // 退回至入口（缺省主线最近已办=n1；并行内节点被过滤，不会命中 ta/tb）
+        taskService.returnBack(SCH, tail.getId(), null, "重新审一遍", 103);
+        FlwInstance returned = instanceRepository.findById(instanceId).get();
+        assertEquals("n1", returned.getCurrentNodes());
+        assertEquals(FlwEnums.InstanceStatus.APPROVING.getCode(), returned.getStatus());
+        // 重入并行段：split 幂等 upsert，不撞 uk(instance,branchKey)
+        taskService.handle(SCH, tasksOf(instanceId, 103).get(0).getId(), true, "再入口", 103);
+        taskService.handle(SCH, tasksOf(instanceId, 101).get(0).getId(), true, "ok", 101);
+        taskService.handle(SCH, tasksOf(instanceId, 102).get(0).getId(), true, "ok", 102);
+        FlwTask n3Again = tasksOf(instanceId, 103).get(0);
+        assertEquals("n3", n3Again.getNodeId());
+        taskService.handle(SCH, n3Again.getId(), true, "复核通过", 103);
+        assertEquals(FlwEnums.InstanceStatus.COMPLETED.getCode(),
+                instanceRepository.findById(instanceId).get().getStatus());
+        // 轨迹含 RETURNED 行
+        assertEquals(1, allTasks(instanceId).stream()
+                .filter(t -> FlwEnums.TaskStatus.RETURNED.getCode() == t.getStatus()).count());
+    }
+
+    @Test
+    void returnBack_noMainlineTarget_throws_andTransfer_reassigns() {
+        mapDept("km", 101, "甲");
+        FlwDef def = saveAndPublishDef("t15", "退回目标", linearDef("km", "首审"));
+        FlowInstanceService.ApplyOutcome outcome = apply(def.getFlowGuid(), "biz-15", 201, "张三");
+        Long instanceId = outcome.getInstanceId();
+        FlwTask task = taskRepository.findByInstanceIdAndStatus(instanceId, 0).get(0);
+        // 首节点无上游已办：缺省退回应明确报错
+        assertThrows(BizException.class, () ->
+                taskService.returnBack(SCH, task.getId(), null, "试试", 101));
+        // 移交：当前任务置 TRANSFERRED，同节点给新办理人建待办
+        taskService.transfer(SCH, task.getId(), 202, "人不在岗", 101);
+        List<FlwTask> handled = allTasks(instanceId);
+        assertEquals(2, handled.size(), "移交后应产生新待办行");
+        assertEquals(FlwEnums.TaskStatus.TRANSFERRED.getCode(), handled.get(0).getStatus());
+        FlwTask reassigned = taskRepository.findByInstanceIdAndStatus(instanceId, 0).get(0);
+        assertEquals(202, reassigned.getAssigneeId());
+        assertEquals(101, handled.get(0).getAssigneeId()); // 原办理人留在轨迹
+        // 新办理人通过 → 完成；已退回/移交后提交人不能撤回
+        taskService.handle(SCH, reassigned.getId(), true, "接手批准", 202);
+        assertEquals(FlwEnums.InstanceStatus.COMPLETED.getCode(),
+                instanceRepository.findById(instanceId).get().getStatus());
+    }
+
     private List<FlwBranch> branchRows(Long instanceId) {
         return branchRepository.findByInstanceId(instanceId);
     }