Amber drops the query string when it rebuilds the callback URL and
appends the signed event directly to the path. The mobile login page now
hands out path-based callback URLs (/auth/mobile/signed/{k1}/) so the
event arrives as the remainder of the path.
The new callback runs in the web middleware group: the signer opens it
in the system browser, which shares cookies with the in-app browser
session, so the flow completes immediately — a bridge page issues the
token and fires the einundzwanzig:// deep link. The LoginKey row is
still written as a fallback for the polling login page.
HolgerHatGarKeineNode