fix(compose): correct Postgres 18 volume mount path for with-db profile

[imKXNNY]

• Problem: docker compose --profile with-db up fails with Postgres 18+ complaining about an "unused mount/volume" at /var/lib/postgresql/data.
• Root cause: compose mounts the named volume at the legacy path (/var/lib/postgresql/data), but Postgres 18+ uses a major-version-specific data layout and expects a single mount at /var/lib/postgresql.
• Fix: mount postgres_data at /var/lib/postgresql (no /data).
• Test (fresh volume recommended):
  docker compose --profile with-db down -v; docker compose --profile with-db up -d --build
  Result: postgres becomes healthy and app-with-db starts successfully.

Windows note: ; works in PowerShell. On Linux/macOS use && to chain commands.

[renecannao]

👍