Two issues:
1. ForwardAuth redirect used x-forwarded-host which Traefik sets to
vibnai.com (the auth service host), not theia.vibnai.com. Now
hardcodes THEIA_URL as the callbackUrl destination.
2. /auth page ignored callbackUrl and always sent users to
/marks-account/projects. Now follows callbackUrl when it points
to theia.vibnai.com, so users land in the IDE after login.
Co-authored-by: Cursor <cursoragent@cursor.com>