Refactor startup event in app.py to streamline knowledge base loading; improve error handling and logging

app.py

@@ -299,29 +299,19 @@ vector_store = None
 async def startup_event():
     global vector_store
     try:
-        # Намеренно вызываем ошибку деления на ноль для рестарта
-        1/0
-    except:
-        pass
-        
-    try:
-        # Сразу запускаем полную пересборку базы знаний
-        vector_store = await build_knowledge_base_async(embeddings, force_rebuild=True)
-        logger.info("Successfully rebuilt knowledge base on startup")
-    except Exception as e:
-        logger.error(f"Failed to rebuild knowledge base on startup: {str(e)}")
-        # Пробуем загрузить существующую базу как fallback
+        # Проверяем существование базы знаний
         if os.path.exists(os.path.join(VECTOR_STORE_PATH, "index.faiss")):
-            try:
-                vector_store = FAISS.load_local(
-                    VECTOR_STORE_PATH,
-                    embeddings,
-                    allow_dangerous_deserialization=True
-                )
-                logger.info("Loaded existing knowledge base as fallback")
-            except Exception as load_error:
-                logger.error(f"Could not load existing knowledge base: {str(load_error)}")
-                vector_store = None
+            vector_store = FAISS.load_local(
+                VECTOR_STORE_PATH,
+                embeddings,
+                allow_dangerous_deserialization=True
+            )
+            logger.info("Existing knowledge base loaded successfully")
+        else:
+            logger.info("No existing knowledge base found. Use /rebuild-kb endpoint to create one")
+    except Exception as e:
+        logger.error(f"Error during startup: {str(e)}")
+        vector_store = None
 
 # API endpoints
 @app.post("/chat", response_model=ChatResponse)