The magic link verification endpoint now returns `requires_signup_completion`
to indicate whether the client needs to collect a name and complete signup.
The signup completion endpoint now supports JSON responses with the account ID.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Addresses an issue where User#familiar_name assumed `name` was always
present, potentially raising an exception during view rendering. Now
User validates name presence, and User#familiar_name handles blank
strings without error, in case any existing invalid records exist.
Rosa Gutierrez