Start Google login

Returns the URL a client should navigate to in order to begin Google OAuth. The URL points to `GET /auth/google`, which redirects the browser to Google's consent screen. After the user consents, the browser is redirected back through `/auth/google/callback` and session cookies are set. For cross-origin SSO, pass `returnTo` (must be allowlisted, or registered to your app via `clientId`) — the callback then redirects to `returnTo?pid_code=...` with a one-time exchange code instead of the wallet. First-time users always land on the PID picker after authenticating (`POST /v1/auth/claim` creates the permanent `<handle>@pid` identity) — handles are only ever chosen there, never up front. Returning logins continue straight to a session.

curl -X POST "https://example.com/auth/login" \  -H "Content-Type: application/json" \  -d '{    "returnTo": "https://mygame.dev/callback",    "clientId": "pidapp_0123456789abcdef0123456789abcdef"  }'

{  "url": "http://localhost:3301/v1/auth/google"}