inkan on Nostr: Thanks, frostr looks like the right thing. Apparently they haven't yet implemented ...

Thanks, frostr looks like the right thing. Apparently they haven't yet implemented NIP-46, but they do have NIP-7. There also seems to be some early stage NIP-55, igloo-android apparently can hold a shard and add its partial signautre, get NIP-55 requests, send signing requests to nodes, and return the signed event. That's very close to what I was asking about, now I just have to actually try it.