Tech Debt: PostgreSQL volume persistence and backup

[smagala]

Description

Configure proper PostgreSQL data persistence and backup strategy for production.

Requirements

• Named volume for PostgreSQL data directory
• Backup strategy (pg_dump scheduled jobs or similar)
• Database initialization scripts
• Connection pooling consideration (PgBouncer if needed)

Context

Identified during #16 Docker containerization work. Current setup uses SQLite for development.

Points: 2

Parent Epic: #30