yeah, 9735 are even more special because the pubkey of the event is not really the pubkey of who originated the action, but perhaps it wouldn't be a terrible idea if zap events included a content of what it is; most clients don't permit responding to a zap event but I think that should definitely be a thing

regardless, I think `content` should be largely reserved for human-readable data

I think json in `content` is an anti-pattern (I did json content in ananostr as one of my first nostr projects and that totally changed my mind)