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

server/src/utils/businessValidationError.js

@@ -0,0 +1,14 @@
+const { AppError } = require("./AppError");
+const { getErrorReason } = require("../constants/errorReasons");
+
+function buildBusinessValidationError(reasonCode, details = {}, statusCode = 400) {
+  const reason = getErrorReason(reasonCode);
+  return new AppError({
+    code: "VALID_001",
+    message: "参数校验失败",
+    statusCode,
+    details: { ...details, reasonCode: reason.code },
+  });
+}
+
+module.exports = { buildBusinessValidationError };