Returned by the comment service's SELECTs on comments, joined with
users for the author_ columns.
id: string
dump_id: string
user_id: string
parent_id: string | null
It is null on a top-level comment.
body: string
created_at: string
updated_at: string | null
deleted: number
1 once deleted. The body is emptied but the row stays, so its replies keep their place in the thread.
like_count: number
author_username: string
author_avatar_mime: string | null