Usernames are auto-assigned at signup (shipped earlier this session)
but there was still no way to change one. Adds a Username field to
Settings, validated client- and server-side against the same
3-20-char lowercase/digits/underscore pattern used for generation,
with a 409 on collision (excluding the user's own current username).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Root cause of "still cannot find users": username was optional in
better-auth's schema and no signup form or settings page ever set it,
but search/profile/follow all key on username, not user id. Every
account now gets a unique one auto-generated (from name/email) in the
user.create.before hook — covers email/password and OAuth signups.
Added a one-off db:backfill-usernames script for accounts created
before this fix and ran it against the current database.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Arnaud