feat: add Nostr NIP-07 browser extension login and invite by pubkey
- Server: nostr crate, migration 008 (nostr_pubkey column), challenge/verify
endpoints for Schnorr-signed NIP-07 auth, invite-by-nostr endpoint
- Client: NIP-07 extension detection, relay profile fetch, Nostr login button
on login/register pages, Nostr tab in invite modal, profile page handles
no-email Nostr users
- Sentinel emails (nostr:<prefix>) hidden at API boundary via public_email()
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Jason Tudisco
1a2f0e7951