fix: 修复 /api/v1/sessions 500 错误

- 修复 validate_ip_and_apikey 装饰器无法获取 Request 对象的问题：
  原代码通过遍历 args 查找 Request 对象，但 FastAPI 端点使用 Pydantic
  模型作为参数时找不到 Request，导致装饰器跳过验证并可能引发异常。
  改为显式声明 request: Request 作为 wrapper 的第一个参数，由 FastAPI 自动注入。

- 增强 ensure_user_hermes_env 的错误处理：
  添加 try/except 包裹，检查 BASE_HERMES_PATH 是否存在，
  将未处理的异常转为带详细信息的 HTTPException(500)。

main.py

@@ -165,22 +165,7 @@ def validate_ip_and_apikey():
     """Decorator to validate IP and API key for protected endpoints"""
     def decorator(func):
         @wraps(func)
-        async def wrapper(*args, **kwargs):
-            # Extract request object (assuming it's the first argument after self)
-            request = None
-            for arg in args:
-                if isinstance(arg, Request):
-                    request = arg
-                    break
-            
-            if request is None:
-                # Try to find request in kwargs
-                request = kwargs.get('request')
-            
-            if request is None:
-                # If no request object found, skip validation
-                return await func(*args, **kwargs)
-            
+        async def wrapper(request: Request, *args, **kwargs):
             # IP validation
             if config['security']['enable_ip_check']:
                 client_ip = get_real_ip(request)
@@ -241,12 +226,15 @@ def get_user_hermes_path(user_id: str) -> str:
 
 def ensure_user_hermes_env(user_id: str):
     """Ensure user has isolated Hermes environment"""
+    try:
         user_base_path = get_user_hermes_path(user_id)
         user_hermes_path = os.path.join(user_base_path, "hermes-agent")
         user_dot_hermes = os.path.join(user_base_path, ".hermes")
         
         if not os.path.exists(user_hermes_path):
             os.makedirs(user_base_path, exist_ok=True, mode=0o700)
+            if not os.path.exists(BASE_HERMES_PATH):
+                raise FileNotFoundError(f"Base Hermes path not found: {BASE_HERMES_PATH}")
             shutil.copytree(
                 BASE_HERMES_PATH,
                 user_hermes_path,
@@ -262,6 +250,13 @@ def ensure_user_hermes_env(user_id: str):
                 )
         
         return user_hermes_path
+    except HTTPException:
+        raise
+    except Exception as e:
+        print(f"ERROR: Failed to ensure user Hermes env for {user_id}: {e}")
+        import traceback
+        traceback.print_exc()
+        raise HTTPException(status_code=500, detail=f"Failed to initialize user environment: {str(e)}")
 
 @app.get("/health")
 @validate_ip_and_apikey()