Returned by the playlist and follow services' SELECTs on playlists,
which join the owner's name as owner_username. A query may add the
dump_count and last_dump_at columns (VISIBLE_DUMP_FIGURES), which
playlistRowToApi carries over when present.
id: string
user_id: string
title: string
slug: string
Unique among its owner's playlists, and set on every row since 0021.
owner_username: string
description: string | null
is_public: number
created_at: string
updated_at: string | null
image_mime: string | null