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/support/FlowTestSupport.java

@@ -103,4 +103,55 @@ public abstract class FlowTestSupport {
     private static String codeOf() {
         return "tc_" + UUID.randomUUID().toString().replace("-", "").substring(0, 8);
     }
+
+    /** 多出口流程：START → n1(deptA，出口"转乙科"→n2 / "通过"→end) → end；n2(deptB) → end */
+    protected String multiOutletDef(String deptA, String deptB) {
+        return "{"
+                + "\"code\":\"" + codeOf() + "\",\"name\":\"多出口测试流程\",\"start\":\"start\","
+                + "\"nodes\":["
+                + "{\"id\":\"start\",\"type\":\"START\",\"name\":\"开始\"},"
+                + "{\"id\":\"n1\",\"type\":\"APPROVAL\",\"name\":\"入口审核\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"" + deptA + "\"}},"
+                + "{\"id\":\"n2\",\"type\":\"APPROVAL\",\"name\":\"复核\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"" + deptB + "\"}},"
+                + "{\"id\":\"end\",\"type\":\"END\"}"
+                + "],"
+                + "\"edges\":[{\"from\":\"start\",\"to\":\"n1\"},"
+                + "{\"from\":\"n1\",\"to\":\"n2\",\"name\":\"转乙科\"},"
+                + "{\"from\":\"n1\",\"to\":\"end\",\"name\":\"通过\"},"
+                + "{\"from\":\"n2\",\"to\":\"end\"}],"
+                + "\"settings\":{\"rejectPolicy\":\"END_REJECTED\"}}";
+    }
+
+    /** 或签流程：START → n1(deptKey, ANY 或签) → END */
+    protected String anyCountersignDef(String deptKey) {
+        return "{"
+                + "\"code\":\"" + codeOf() + "\",\"name\":\"夡签测试流程\",\"start\":\"start\","
+                + "\"nodes\":["
+                + "{\"id\":\"start\",\"type\":\"START\",\"name\":\"开始\"},"
+                + "{\"id\":\"n1\",\"type\":\"APPROVAL\",\"name\":\"任一人审批\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"" + deptKey + "\"},\"countersign\":\"ANY\"},"
+                + "{\"id\":\"end\",\"type\":\"END\"}"
+                + "],"
+                + "\"edges\":[{\"from\":\"start\",\"to\":\"n1\"},{\"from\":\"n1\",\"to\":\"end\"}],"
+                + "\"settings\":{\"rejectPolicy\":\"END_REJECTED\"}}";
+    }
+
+    /** 主线带并行段：START → n1(deptA) → split → {ta(ka), tb(kb)} → join → n3(deptA) → END（退回重入用） */
+    protected String mainlineParallelTailDef(String deptA, String deptMain) {
+        return "{"
+                + "\"code\":\"" + codeOf() + "\",\"name\":\"主线并行尾验流程\",\"start\":\"start\","
+                + "\"nodes\":["
+                + "{\"id\":\"start\",\"type\":\"START\",\"name\":\"开始\"},"
+                + "{\"id\":\"n1\",\"type\":\"APPROVAL\",\"name\":\"入口\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"" + deptMain + "\"}},"
+                + "{\"id\":\"split1\",\"type\":\"PARALLEL_SPLIT\"},"
+                + "{\"id\":\"ta\",\"type\":\"APPROVAL\",\"name\":\"甲科审核\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"ka\"}},"
+                + "{\"id\":\"tb\",\"type\":\"APPROVAL\",\"name\":\"乙科审核\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"kb\"}},"
+                + "{\"id\":\"join1\",\"type\":\"PARALLEL_JOIN\",\"waitFor\":\"ALL\"},"
+                + "{\"id\":\"n3\",\"type\":\"APPROVAL\",\"name\":\"出口复核\",\"assignee\":{\"type\":\"DEPT_KEY\",\"deptKey\":\"" + deptA + "\"}},"
+                + "{\"id\":\"end\",\"type\":\"END\"}"
+                + "],"
+                + "\"edges\":[{\"from\":\"start\",\"to\":\"n1\"},{\"from\":\"n1\",\"to\":\"split1\"},"
+                + "{\"from\":\"split1\",\"to\":\"ta\"},{\"from\":\"split1\",\"to\":\"tb\"},"
+                + "{\"from\":\"ta\",\"to\":\"join1\"},{\"from\":\"tb\",\"to\":\"join1\"},"
+                + "{\"from\":\"join1\",\"to\":\"n3\"},{\"from\":\"n3\",\"to\":\"end\"}],"
+                + "\"settings\":{\"rejectPolicy\":\"END_REJECTED\"}}";
+    }
 }