feat(i18n): 管理端与玩家端三语支持（中/英/马来语）

- 管理后台 adminT 文案库、结算与代理端页面、表单校验
- 玩家端 vue-i18n 补全首页/公告/串关与 ms 文案
- Element Plus ms 语言包与共享 locale 工具

apps/api/src/domains/identity/users.service.ts

@@ -1,4 +1,5 @@
 import { BadRequestException, Injectable, NotFoundException } from '@nestjs/common';
+import { SUPPORTED_LOCALES } from '@thebet365/shared';
 import { PrismaService } from '../../shared/prisma/prisma.service';
 import { AgentsService } from '../agent/agents.service';
 
@@ -92,6 +93,9 @@ export class UsersService {
   }
 
   async updateLocale(userId: bigint, locale: string) {
+    if (!(SUPPORTED_LOCALES as readonly string[]).includes(locale)) {
+      throw new BadRequestException('Unsupported locale');
+    }
     await this.prisma.user.update({
       where: { id: userId },
       data: { locale },