fix(admin): 预种开关DTO添加class-validator装饰器，修复400错误

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/services/admin-service/src/pre-planting/pre-planting-config.controller.ts

@@ -9,15 +9,21 @@ import {
   HttpStatus,
 } from '@nestjs/common';
 import { ApiTags, ApiOperation, ApiResponse, ApiQuery } from '@nestjs/swagger';
+import { IsBoolean, IsOptional, IsString } from 'class-validator';
 import { PrePlantingConfigService } from './pre-planting-config.service';
 import { PrePlantingProxyService } from './pre-planting-proxy.service';
 
 class UpdatePrePlantingConfigDto {
+  @IsBoolean()
   isActive: boolean;
+
+  @IsOptional()
+  @IsString()
   updatedBy?: string;
 }
 
 class TogglePrePlantingConfigDto {
+  @IsBoolean()
   isActive: boolean;
 }