you are NOT supposed to broadcast kind 22242, it must be sent to relays on demand only
so I probably have none.
The implementation should check:
- created_at is within tolerances (like 30s, depends on relay)
- that there is one relay tag with the relay URL. Rough matches should work, like: wss://nostr.land and wss://nostr.land/
- there is only one challenge tag which should be the relay sent challenge