fix: 修复 NameError/状态污染/类型标注/统计; 补全练习与 main; 新增 config/.gitignore/requirements; 文档统一

step_02_state/__init__.py

@@ -0,0 +1,5 @@
+# Jaspersoft Learn - Step 02: 状态管理
+
+from .concept import AgentState, JaspersoftAgentState
+
+__all__ = ["AgentState", "JaspersoftAgentState"]

step_02_state/concept.py

@@ -12,9 +12,8 @@ Step 02: 理解 State - 状态管理
 """
 
 from typing import TypedDict, List, Dict, Any, Optional
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from datetime import datetime
-import json
 
 
 # ═══════════════════════════════════════════════════════════════════════════════

step_02_state/exercise.py

@@ -12,7 +12,6 @@ Step 02 练习题：设计你的第一个 Agent State
 """
 
 from typing import TypedDict, List, Dict, Any
-import json
 
 
 # ═══════════════════════════════════════════════════════════════════════════════