Zero-Downtime Fail-Safe & Automated Rollback Suite for Legacy Database Schema Mi

<h2> The Problem </h2> <p>You write a Supabase migration, it runs fine locally. You push to staging — fine. Then you need to re-apply it (rollback test, fresh CI environment, or a

<blockquote> <p>A complete technical breakdown of how FastAPI, SQLAlchemy, asyncpg, PostgreSQL, Declarative Base, and Alembic work together as a production system - covering