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/scripts/error-reason-client.test.js

@@ -2,7 +2,7 @@ const fs = require("node:fs");
 const path = require("node:path");
 const ts = require("../../../../client/node_modules/typescript");
 const expectedMessages = require("../fixtures/error-reason-messages.json");
-const { getErrorReason } = require("../../../src/constants/errorReasons");
+const { ERROR_REASONS, getErrorReason } = require("../../../src/constants/errorReasons");
 const { getMissingRequiredOcrFields } = require("../../../src/services/ocr");
 const { validatePassword } = require("../../../src/utils/passwordPolicy");
 
@@ -32,6 +32,13 @@ describe("client business error projection", () => {
     expect(formatDisplayDateTime("2026-12-31T18:30:45.000Z", { includeSeconds: true })).toBe("2027年1月1日 02:30:45");
   });
 
+  it("requires an independent message fixture for every user-facing registered reason", () => {
+    const missing = ERROR_REASONS
+      .filter((reason) => reason.audience === "user" && !Object.hasOwn(expectedMessages, reason.code))
+      .map((reason) => reason.code);
+    expect(missing).toEqual([]);
+  });
+
   it.each(Object.entries(expectedMessages))("keeps exact registered and displayed content for %s", (reasonCode, expected) => {
     expect(getErrorReason(reasonCode).defaultMessage).toBe(expected);
     expect(resolveErrorMessage(new ApiError({ status: 409, code: "VALID_001", message: "private payload", details: { reasonCode } }))).toBe(expected);