A tag interface plus a runtime discriminator

A tag carries no members. It exists so that unrelated classes — persistence rows, search results, locally created records — can appear in one list and be accepted by one renderer:

interface HomeContentType
interface LibraryType

Where the renderer genuinely has to branch, the tag adds a nested enum and one accessor:

interface PlaylistType : HomeContentType, LibraryType {
    enum class Type { REMOTE, RADIO, LOCAL, ALBUM, SERIES }
    fun playlistType(): Type
}