FIX: Use langchain_classic.memory for ConversationBufferWindowMemory (langchain 0.3.27 has memory under langchain_classic, not langchain)

src/agent/memory_manager.py

@@ -1,4 +1,4 @@
-from langchain.memory import ConversationBufferWindowMemory
+from langchain_classic.memory import ConversationBufferWindowMemory
 from typing import Dict, Any, List, Optional
 
 class MemoryManager:

src/agent/research_agent.py

@@ -1,6 +1,6 @@
 from langchain_google_genai import ChatGoogleGenerativeAI
 from langchain_community.llms import Ollama
-from langchain.memory import ConversationBufferWindowMemory
+from langchain_classic.memory import ConversationBufferWindowMemory
 from typing import List, Dict, Any
 import asyncio
 from datetime import datetime