fix(identity-service): 添加 DTO 验证装饰器

- 为 BatchGetUsersBySequenceDto 添加 class-validator 装饰器
- 修复 ValidationPipe 验证失败问题

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/identity-service/src/api/controllers/internal.controller.ts

@@ -1,5 +1,6 @@
 import { Controller, Post, Body, Get, Param, Logger } from '@nestjs/common';
-import { ApiTags, ApiOperation, ApiResponse } from '@nestjs/swagger';
+import { ApiTags, ApiOperation, ApiResponse, ApiProperty } from '@nestjs/swagger';
+import { IsArray, IsString } from 'class-validator';
 import { Public } from '@/shared/guards/jwt-auth.guard';
 import { UserAccountRepositoryImpl } from '@/infrastructure/persistence/repositories/user-account.repository.impl';
 import { AccountSequence } from '@/domain/value-objects';
@@ -8,6 +9,9 @@ import { AccountSequence } from '@/domain/value-objects';
  * 批量获取用户信息请求 DTO (按 accountSequence)
  */
 class BatchGetUsersBySequenceDto {
+  @ApiProperty({ description: '账户序列号列表', example: ['2412230001', '2412230002'] })
+  @IsArray()
+  @IsString({ each: true })
   accountSequences: string[];
 }