Add song shuffle

The playlist still plays in the order it was contributed, from the top, round again at the end. Shuffle is the other order, and a shuffle has a name.

?seed=omarchy is that name, and the address is the only copy of it. Same name, same order: next and previous both walk it, so two people on the link hear the same song come next. The rows do not move. A link to a song still opens that song — the seed says which shuffle it sits in, and the path says where you enter it. A new song slots in where the name puts it and does not reshuffle the rest.

The canonical link leaves the seed off. A shuffled deck is a way of listening, not a different page. Open the front page and it plays in order; open ?seed=omarchy and it is that shuffle, for as long as the address says so. Turning shuffle on mints a name and puts it there; turning it off takes it off.

It is the playlist's. An episode is a show, and the next episode is the next episode.

The ground takes the same name, once, when the visit opens. The bars under the clock are not random: they are the record, or a stand-in that moves with the clock when the record cannot be heard.

The order is src/lib/order.ts. The deck walks it; npm test walks the same functions.