28dc79d0b7
The SMTP send (connect → TLS → login → handoff to the relay) ran synchronously inside POST /api/auth/email/start, so the "Sending…" button waited the whole handshake. Move it to a FastAPI BackgroundTask: the token is created + committed, the request returns immediately, and the email sends off the request path. Reply stays identical (no account enumeration). Tests pass (TestClient runs the task). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>