feat: 增加结构化日志和服务就绪检查

ai_knowledge_base_v2/apps/backend/app/main.py

@@ -9,6 +9,7 @@ from app.api.router import api_router
 from app.core.config import get_settings
 from app.core.database import create_tables
 from app.core.exception_handlers import register_exception_handlers
+from app.core.observability import RequestObservabilityMiddleware, configure_logging
 from app.services.secret_service import SecretService
 
 
@@ -22,9 +23,11 @@ async def lifespan(app: FastAPI):
 
 
 settings = get_settings()
+configure_logging(settings.log_level)
 
 app = FastAPI(title=settings.app_name, version="0.1.0", lifespan=lifespan)
 register_exception_handlers(app)
+app.add_middleware(RequestObservabilityMiddleware)
 
 app.add_middleware(
     CORSMiddleware,