Migration-Guard: Safe & Reversible Schema Evolution

Prevent catastrophic schema migrations, unrecoverable data loss, and locking deadlocks in relational databases.

The repository's own migration procedure (its AGENTS.md or README) wins over this checklist. For a broader rollout plan, the user can explicitly invoke migration; do not load it automatically.

4 Golden Migration Rules

1. Reversibility:
   • Every forward migration (up.sql) must have a corresponding tested rollback migration (down.sql).
   • Drizzle and Prisma generate forward migrations only: write the rollback by hand. Prisma can draft one with prisma migrate diff from the new schema to the previous one with --script (see Prisma's "Generating down migrations" guide).