fix(wallet-service): 修复系统划转请求 DTO 验证错误

- 为 SystemWithdrawalRequestDTO 添加 class-validator 装饰器
- 添加 @ApiProperty 装饰器用于 Swagger 文档
- 使用 @Type(() => Number) 自动转换 amount 类型
- 简化验证逻辑，移除冗余的手动验证

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

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

backend/services/wallet-service/src/api/controllers/system-withdrawal.controller.ts

@@ -19,18 +19,43 @@ import {
   ApiOperation,
   ApiResponse,
   ApiQuery,
-  ApiBody,
+  ApiProperty,
 } from '@nestjs/swagger';
+import { IsString, IsNotEmpty, IsOptional, IsNumber } from 'class-validator';
+import { Type } from 'class-transformer';
 import { Public } from '@/shared/decorators';
 import { SystemWithdrawalApplicationService } from '@/application/services';
 
 // DTO 定义
 class SystemWithdrawalRequestDTO {
+  @ApiProperty({ description: '转出方系统账户序列号', example: 'S0000000003' })
+  @IsString()
+  @IsNotEmpty()
   fromAccountSequence: string;
+
+  @ApiProperty({ description: '接收方用户充值ID', example: 'D25122800032' })
+  @IsString()
+  @IsNotEmpty()
   toAccountSequence: string;
-  amount: number | string;  // 支持字符串或数字
+
+  @ApiProperty({ description: '转出金额（绿积分）', example: 1000 })
+  @Type(() => Number)
+  @IsNumber()
+  amount: number;
+
+  @ApiProperty({ description: '备注', required: false, example: '补发奖励' })
+  @IsString()
+  @IsOptional()
   memo?: string;
+
+  @ApiProperty({ description: '操作管理员ID', example: 'admin_001' })
+  @IsString()
+  @IsNotEmpty()
   operatorId: string;
+
+  @ApiProperty({ description: '操作管理员姓名', required: false, example: '管理员张三' })
+  @IsString()
+  @IsOptional()
   operatorName?: string;
 }
 
@@ -56,70 +81,20 @@ export class SystemWithdrawalController {
     summary: '发起系统账户转出（内部API）',
     description: '从系统账户（总部、运营、区域等）转出资金到用户账户',
   })
-  @ApiBody({
-    schema: {
-      type: 'object',
-      required: ['fromAccountSequence', 'toAccountSequence', 'amount', 'operatorId'],
-      properties: {
-        fromAccountSequence: {
-          type: 'string',
-          description: '转出方系统账户序列号',
-          example: 'S0000000003',
-        },
-        toAccountSequence: {
-          type: 'string',
-          description: '接收方用户充值ID',
-          example: 'D25122800032',
-        },
-        amount: {
-          type: 'number',
-          description: '转出金额（绿积分）',
-          example: 1000,
-        },
-        memo: {
-          type: 'string',
-          description: '备注',
-          example: '补发奖励',
-        },
-        operatorId: {
-          type: 'string',
-          description: '操作管理员ID',
-          example: 'admin_001',
-        },
-        operatorName: {
-          type: 'string',
-          description: '操作管理员姓名',
-          example: '管理员张三',
-        },
-      },
-    },
-  })
   @ApiResponse({ status: 200, description: '转出订单创建成功' })
   @ApiResponse({ status: 400, description: '参数错误或余额不足' })
   async requestSystemWithdrawal(@Body() dto: SystemWithdrawalRequestDTO) {
     this.logger.log(`[REQUEST] 系统账户转出请求: ${JSON.stringify(dto)}`);
 
-    // 验证必填参数
-    if (!dto.fromAccountSequence) {
-      throw new BadRequestException('转出账户不能为空');
-    }
-    if (!dto.toAccountSequence) {
-      throw new BadRequestException('接收账户不能为空');
-    }
-
-    // 将 amount 转换为数字（前端可能传入字符串）
-    const amount = typeof dto.amount === 'string' ? parseFloat(dto.amount) : dto.amount;
-    if (!amount || isNaN(amount) || amount <= 0) {
+    // class-validator 已处理基本验证，这里只做业务验证
+    if (dto.amount <= 0) {
       throw new BadRequestException('转出金额必须大于0');
     }
-    if (!dto.operatorId) {
-      throw new BadRequestException('操作员ID不能为空');
-    }
 
     const result = await this.systemWithdrawalService.requestSystemWithdrawal({
       fromAccountSequence: dto.fromAccountSequence,
       toAccountSequence: dto.toAccountSequence,
-      amount: amount,
+      amount: dto.amount,
       memo: dto.memo,
       operatorId: dto.operatorId,
       operatorName: dto.operatorName,