I was thinking bout this one since #amethyst seems to support it https://github.com/nostr-protocol/nips/blob/master/94.md
I don't think the problem is storing the hash/magnet rather gaining a consensus on which p2p protocol to use if any.
Web torrent is a torrent only in name - since webrtc was designed by centralized people. (Every single peer connection has to be brokered by a server.)
Ipfs is a cesspit of bloat/complexity. (Will never run on user devices)
Regular torrents, well cool but only makes sense for bigfiles and non-browser clients.
If we can somehow gather all "security experts", ship them off to an island and leave them to enjoy the great debate.
Then we might just have enough time to patch browsers with lowlevel DHT api's and let people figure out the rest 🙂