Is there a write up of how the signing server works?
the answer is simply, never to put keys into web apps. Use external signers (not extensions).
Native apps (amethyst/damus) could provide this facility, or the upcoming signing server from nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft
Is there a write up of how the signing server works?
there's also NIP 46