fix env load bug

code/chapter8/01_MemoryTool_Basic_Operations.py

@@ -5,11 +5,11 @@
 展示MemoryTool的核心execute方法和基本操作
 """
 
+from dotenv import load_dotenv
+load_dotenv()
 from datetime import datetime
 from typing import List
 from hello_agents.tools import MemoryTool
-from dotenv import load_dotenv
-load_dotenv()
 
 def memory_tool_execute_demo():
     """MemoryTool execute方法演示"""

code/chapter8/02_MemoryTool_Architecture.py

@@ -5,12 +5,12 @@
 展示MemoryTool和MemoryManager的分层架构
 """
 
+from dotenv import load_dotenv
+load_dotenv()
 from typing import List, Optional, Dict, Any
 from datetime import datetime
 from hello_agents.tools import MemoryTool
 from hello_agents.memory import MemoryConfig
-from dotenv import load_dotenv
-load_dotenv()
 
 class MemoryToolArchitectureDemo:
     """MemoryTool架构演示类"""

code/chapter8/06_Memory_Consolidation_Demo.py

@@ -5,11 +5,12 @@
 展示从短期记忆到长期记忆的智能转化过程
 """
 
+from dotenv import load_dotenv
+load_dotenv()
 import time
 from datetime import datetime, timedelta
 from hello_agents.tools import MemoryTool
-from dotenv import load_dotenv
-load_dotenv()
+
 
 class MemoryConsolidationDemo:
     """记忆整合演示类"""

code/chapter8/08_Agent_Tool_Integration.py

@@ -5,11 +5,11 @@
 展示如何在HelloAgents框架中集成MemoryTool和RAGTool
 """
 
+from dotenv import load_dotenv
+load_dotenv()
 import time
 from hello_agents import SimpleAgent, HelloAgentsLLM, ToolRegistry
 from hello_agents.tools import MemoryTool, RAGTool
-from dotenv import load_dotenv
-load_dotenv()
 
 class AgentIntegrationDemo:
     """Agent工具集成演示类"""

code/chapter8/09_Memory_Types_Deep_Dive.py

@@ -5,14 +5,14 @@
 详细展示WorkingMemory、EpisodicMemory、SemanticMemory、PerceptualMemory的实现特点
 """
 
+from dotenv import load_dotenv
+load_dotenv()
 import os
 import time
 import hashlib
 from datetime import datetime, timedelta
 from typing import List, Dict, Any, Optional
 from hello_agents.tools import MemoryTool
-from dotenv import load_dotenv
-load_dotenv()
 
 class MemoryTypesDeepDive:
     """四种记忆类型深度解析演示类"""

code/chapter8/11_Q&A_Assistant.py

@@ -10,6 +10,8 @@
 - 学习回顾和报告生成
 """
 
+from dotenv import load_dotenv
+load_dotenv()
 import os
 import time
 import json
@@ -17,8 +19,6 @@ from datetime import datetime
 from typing import Dict, List, Optional, Any, Tuple
 from hello_agents.tools import MemoryTool, RAGTool
 import gradio as gr
-from dotenv import load_dotenv
-load_dotenv()
 
 class PDFLearningAssistant:
     """智能文档问答助手"""