T-2 was "Dockerfile + configuration" but database connectivity cannot be meaningfully verified without JPA and migrations (T-4). Split: T-2 focuses on the multi-stage Dockerfile, T-4 absorbs DATABASE_URL config, env vars, and docker-compose documentation. Updated dependency graph and Mermaid diagram accordingly. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>