feat:翻译长度限制

src/controller/translate/dto/req/translateReq.dto.ts

 import { SupportLanguages } from '@/common/utils/constants';
 import { ApiProperty } from '@nestjs/swagger';
 import { Expose } from 'class-transformer';
-import { IsEnum, IsNotEmpty, IsString } from 'class-validator';
+import { IsEnum, IsNotEmpty, IsString, Length } from 'class-validator';
 
 export class TranslateReqDto {
   @ApiProperty({
@@ -32,5 +32,6 @@ export class TranslateReqDto {
   @Expose()
   @IsNotEmpty()
   @IsString()
+  @Length(1, 200)
   text: string;
 }