Add test_protected_phrases.py covering phrase-matching behavior in the RAG engine, and update the existing ebook_search tests to use the async SQLAlchemy engine/session (create_async_engine, AsyncSession) and async HTTP paths.
Add test_protected_phrases.py covering phrase-matching behavior in the RAG engine, and update the existing ebook_search tests to use the async SQLAlchemy engine/session (create_async_engine, AsyncSession) and async HTTP paths.