when merging frontend and backend, reuse and merge this with the frontend model

[github-actions]

https://api.github.com/fujaba/fulib.org/blob/5ff763332bb1a10da1d53a8cf25d5182fe37d7b8/services/apps/assignments/src/solution/solution.schema.ts#L38

  '3P'?: boolean;
}

// TODO when merging frontend and backend, reuse and merge this with the frontend model
export class Feedback {
  @IsOptional()
  @IsIn([1, 2, 3, 4])
  appropriate?: number;

  @IsOptional()
  @IsIn([1, 2, 3, 4])
  helpful?: number;

  @IsOptional()
  @IsIn([1, 2, 3, 4])
  understandable?: number;
}

export class AuthorInfo {
  @Prop()
  @ApiPropertyOptional()