Avoids conflicts with any system services (PostgreSQL, MinIO) that
may already occupy 5432/9000/9001 on the runner host.
DB: 5433, MinIO API: 9100, MinIO console: 9101.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Port 5432 was already in use after docker compose cleanup because a
system-level PostgreSQL service on the runner host holds the port.
Also kill any stray containers binding to 5432/9000/9001.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>