feat(challenges): 更新自定义挑战功能，支持时间戳转换及数据模型调整

src/challenges/dto/create-custom-challenge.dto.ts

@@ -77,23 +77,6 @@ export class CreateCustomChallengeDto {
   @MaxLength(255)
   rankingDescription?: string;
 
-  @ApiProperty({ description: '高亮标题', example: '坚持21天', required: false })
-  @IsString()
-  @IsOptional()
-  @MaxLength(255)
-  highlightTitle?: string;
-
-  @ApiProperty({ description: '高亮副标题', example: '养成好习惯', required: false })
-  @IsString()
-  @IsOptional()
-  @MaxLength(255)
-  highlightSubtitle?: string;
-
-  @ApiProperty({ description: 'CTA 按钮文字', example: '立即加入', required: false })
-  @IsString()
-  @IsOptional()
-  @MaxLength(128)
-  ctaLabel?: string;
 
   @ApiProperty({ description: '是否公开（可通过分享码加入）', default: true })
   @IsBoolean()