Feature Pack 004: PostgreSQL Database Replacement

Status: Implemented Track: architecture Previous state: 003-containerized-compose-runtime

This pack defines an architecture-track branch from 003-containerized-compose-runtime that replaces the runtime database engine from H2 to PostgreSQL while preserving baseline functional behavior.

Primary intent:

• replace H2 with PostgreSQL in Docker Compose runtime,
• keep baseline REST/event contracts stable,
• keep startup and smoke validation deterministic,
• keep generation fully spec-first and reproducible.

Core artifacts:

• spec.md
• requirements/functional-delta.md
• requirements/nonfunctional-delta.md
• contracts/contract-delta.md
• system/architecture.model.json
• system/runtime-topology.md
• generation/generation-hook.md
• tests/smoke/README.md

Additional artifacts:

• components/postgres-database.md
• conformance/postgres-database.md
• system/docker-compose.postgres.snippet.yaml
• system/postgres-migration-guidance.md
• fidelity-profile.md

Decision record:

• ADR: docs/adr/006-state-004-use-postgres-for-database-replacement.md