The refresh endpoint only returned access_token, causing the frontend to
set refreshToken=undefined after first refresh — breaking the entire
token chain. Now returns both tokens (rotating refresh). Access token
default bumped from 15min to 4h (14400s) for practical server setup
sessions. Also fixed empty license_key for super admin via DB update.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>