Add guaranteed UAT test user (uat@cartsnitch.com / CartSnitch-UAT-2026!)
seeded via Better-Auth bcrypt path. Idempotent — re-running the seed
skips the user if it already exists.
- Add 002_better_auth_tables Alembic migration (sessions, accounts,
verifications tables + email_verified/image on users)
- Add bcrypt>=4.0,<6.0 to [seed] extra (CTO feedback: was bcrypt>=0.15,<1.0
which matches zero installable versions)
- Fix account_id to use str(UAT_USER_ID) to match migration convention
(CTO feedback: was using UAT_EMAIL which was inconsistent)
- Document credentials in common/README.md under Test Users
Co-Authored-By: Paperclip <noreply@paperclip.ing>