feat: internationalize API error responses by locale

Add shared error codes with zh/en/ms messages, coded app exceptions,
and locale-aware global filter. Frontends send X-Locale so error text
matches the active UI language.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/src/domains/operations/cashback/cashback.service.ts

@@ -1,9 +1,10 @@
-import { Injectable, BadRequestException } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import { Prisma } from '@prisma/client';
 import { PrismaService } from '../../../shared/prisma/prisma.service';
 import { WalletService } from '../../ledger/wallet.service';
 import { Decimal } from '@prisma/client/runtime/library';
 import { generateBatchNo } from '../../../shared/common/decorators';
+import { appBadRequest } from '../../../shared/common/app-error';
 import {
   resolveCashbackRateForBet,
   type CashbackRuleRow,
@@ -214,14 +215,14 @@ export class CashbackService {
     const start = this.normalizePeriodStart(periodStart);
     const end = this.normalizePeriodEnd(periodEnd);
     if (start > end) {
-      throw new BadRequestException('开始日期不能晚于结束日期');
+      throw appBadRequest('CASHBACK_DATE_RANGE_INVALID');
     }
 
     const alreadyPaid = await this.prisma.cashbackBatch.findFirst({
       where: { status: 'CONFIRMED', periodStart: start, periodEnd: end },
     });
     if (alreadyPaid) {
-      throw new BadRequestException('该统计周期已发放返水，不可重复生成预览');
+      throw appBadRequest('CASHBACK_ALREADY_ISSUED');
     }
 
     const {
@@ -236,9 +237,9 @@ export class CashbackService {
 
     if (items.length === 0 || totalAmount.lte(0)) {
       if (eligibleBetCount > 0 && skippedClaimedCount >= eligibleBetCount) {
-        throw new BadRequestException('该周期内的有效注单均已计入其他返水批次，无法生成预览');
+        throw appBadRequest('CASHBACK_BETS_IN_OTHER_BATCH');
       }
-      throw new BadRequestException('该周期内无符合条件的返水，无法生成预览');
+      throw appBadRequest('CASHBACK_NO_ELIGIBLE_BETS');
     }
 
     let batch!: Awaited<ReturnType<typeof this.prisma.cashbackBatch.create>>;
@@ -345,7 +346,7 @@ export class CashbackService {
         items: { orderBy: { amount: 'desc' } },
       },
     });
-    if (!batch) throw new BadRequestException('Batch not found');
+    if (!batch) throw appBadRequest('CASHBACK_BATCH_NOT_FOUND');
 
     const userIds = batch.items.map((i) => i.userId);
     const users =
@@ -403,10 +404,10 @@ export class CashbackService {
       where: { id: batchId },
       include: { items: true, bets: true },
     });
-    if (!batch) throw new BadRequestException('Batch not found');
-    if (batch.status !== 'PREVIEW') throw new BadRequestException('该批次不可发放');
+    if (!batch) throw appBadRequest('CASHBACK_BATCH_NOT_FOUND');
+    if (batch.status !== 'PREVIEW') throw appBadRequest('CASHBACK_BATCH_NOT_ISSUABLE');
     if (batch.items.length === 0 || batch.totalAmount.lte(0)) {
-      throw new BadRequestException('批次无有效返水金额');
+      throw appBadRequest('CASHBACK_NO_AMOUNT');
     }
 
     const duplicate = await this.prisma.cashbackBatch.findFirst({
@@ -418,7 +419,7 @@ export class CashbackService {
       },
     });
     if (duplicate) {
-      throw new BadRequestException('该统计周期已发放返水');
+      throw appBadRequest('CASHBACK_PERIOD_ALREADY_ISSUED');
     }
 
     const betIds = batch.bets.map((b) => b.betId);
@@ -430,7 +431,7 @@ export class CashbackService {
         },
       });
       if (conflict) {
-        throw new BadRequestException('部分注单已在其他批次发放返水，请作废本预览后重新生成');
+        throw appBadRequest('CASHBACK_BETS_ALREADY_PAID');
       }
     }
 
@@ -457,9 +458,9 @@ export class CashbackService {
 
   async cancelBatch(batchId: bigint) {
     const batch = await this.prisma.cashbackBatch.findUnique({ where: { id: batchId } });
-    if (!batch) throw new BadRequestException('Batch not found');
+    if (!batch) throw appBadRequest('CASHBACK_BATCH_NOT_FOUND');
     if (batch.status !== 'PREVIEW') {
-      throw new BadRequestException('只能作废待发放批次');
+      throw appBadRequest('CASHBACK_PREVIEW_ONLY_VOID');
     }
 
     await this.prisma.$transaction(async (tx) => {