feat: 完成错误原因合同与付款就绪提示（09-05-error-explainability-payment-readiness）

client/src/api/errorMessages.ts

@@ -1,4 +1,5 @@
 import { formatInvoiceOcrFieldLabels } from "../lib/invoiceOcr";
+import { resolveErrorReasonMessage, UNKNOWN_VALIDATION_MESSAGE } from "./errorReasons";
 
 function readStringList(value: unknown): string[] {
   if (!Array.isArray(value)) {
@@ -71,7 +72,13 @@ export function mapApiErrorMessage(
   code: string,
   details?: Record<string, unknown>,
   fallbackMessage?: string,
-) {
+): string {
+  if (code === "VALID_001" && details?.reasonCode === "reimbursement.items_invoice_item_guard_failed") {
+    return mapApiErrorMessage(code, { ...details, reasonCode: undefined, items: "invoice_item_guard_failed" });
+  }
+  if (code === "VALID_001" && details?.reasonCode !== undefined) {
+    return resolveErrorReasonMessage(details.reasonCode) ?? UNKNOWN_VALIDATION_MESSAGE;
+  }
   if (code === "AUTH_001") {
     return "账号或密码错误，请检查后重试。";
   }
@@ -512,5 +519,5 @@ export function mapApiErrorMessage(
     }
   }
 
-  return fallbackMessage || "请求失败，请稍后重试。";
+  return code === "VALID_001" ? UNKNOWN_VALIDATION_MESSAGE : fallbackMessage || "请求失败，请稍后重试。";
 }