feat(dependencies): update database engine dependencies to support async operations

python/ebook_search/api/dependencies.py

@@ -6,7 +6,6 @@ from typing import Annotated
 
 import httpx
 from fastapi import Depends, Request
-from sqlalchemy.ext.asyncio import AsyncEngine
 
 from python.ebook_search.config import EbookSearchConfig
 
@@ -16,16 +15,10 @@ def get_config(request: Request) -> EbookSearchConfig:
     return request.app.state.config
 
 
-def get_engine(request: Request) -> AsyncEngine:
-    """Get the database engine from app state."""
-    return request.app.state.engine
-
-
 def get_http_client(request: Request) -> httpx.AsyncClient:
     """Get the shared LLM HTTP client from app state."""
     return request.app.state.http_client
 
 
 AppConfig = Annotated[EbookSearchConfig, Depends(get_config)]
-AppEngine = Annotated[AsyncEngine, Depends(get_engine)]
 AppHttpClient = Annotated[httpx.AsyncClient, Depends(get_http_client)]