完善借款、编号、付款与预算并发及验收（09-06-release-gate-integrity）

汇总已落盘的借款本金与还款、兼容历史编号的周期化编号、付款责任与回单核验、报销进度和排序、PWA/采购事务、错误原因与日期校验及ERP退役。
统一共享预算池锁序和锁后判断，恢复差旅原预算选择，补原因码固定夹具及反向完整性检查。
纳入配套迁移、测试、受管QA、分层验收合同、规约及任务记录；原始证据留在ignored artifacts。

关联任务：09-17-company-loan-principal-repayment、09-17-erp-exclusive-retirement、09-18-reimbursement-periodic-numbering、09-08-reimbursement-payment-closeout、09-18-local-concurrency-product-fixes、09-19-budget-pool-concurrency、09-05-error-explainability-payment-readiness。
预算补审由Claude定向验证2文件928项通过，原4446/28及r6结果仍仅对应各自历史输入；本轮未重跑测试。
完整新候选门禁、R1真实入口接入与12项公网义务仍开放。生产编号未启用、差旅仍冻结；不推送、不部署，不宣称发布资格。

server/tests/unit/routes/performance.cycles.test.js

@@ -246,3 +246,17 @@ describe("performance cycle routes", () => {
     await app.close();
   });
 });
+
+describe("performance cycle calendar boundary", () => {
+  it("preserves leap day, month end and a partial date patch", async () => {
+    const { app, state, performanceReviewCycle } = await buildApp();
+    try {
+      const response = await app.inject({ method: "POST", url: "/api/performance/cycles", payload: { name: "合成周期", cycleType: "quarterly", startDate: "2024-02-29", endDate: "2024-04-30" } });
+      expect(response.statusCode).toBe(200);
+      expect(response.json().data).toMatchObject({ startDate: "2024-02-29", endDate: "2024-04-30" });
+      expect((await app.inject({ method: "PATCH", url: `/api/performance/cycles/${state.cycles[0].id}`, payload: { endDate: "2024-05-31" } })).statusCode).toBe(200);
+      expect(performanceReviewCycle.update.mock.calls[0][0].data).toMatchObject({ end_date: new Date("2024-05-31T00:00:00Z") });
+      expect(performanceReviewCycle.update.mock.calls[0][0].data).not.toHaveProperty("start_date");
+    } finally { await app.close(); }
+  });
+});