From a webapp I guess I need to trigger an "intent" or some kind of uri scheme protocol so that login button open nsec.app to sign users in...
Don't know exactly which one but I'll figure it out.
Discussion
If your app already works with key storage extensions (nip-07, window.nostr) then you can use nostr-login library - two lines of code and all your calls to window.nostr are proxied to nip46 remote signing, with a pretty UI showing up for users to login/signup.
Yes I do the window.nostr(event) now.
this one? https://www.npmjs.com/package/nostr-login
there's a github?