Add a self-contained docker/ package for running the ebook search app
against the existing Postgres database on jeeves:
- Dockerfile: python:3.14-slim image, non-root user, runs the FastAPI
app on port 8070
- docker-compose.yml: service definition with library volume mount,
BM25 index volume, .env loading, and a /health healthcheck
- containers.py: Typer CLI (ebook-search-containers) for build/start/
stop/restart/logs/ps lifecycle management
- README.md: usage and configuration docs
