perfect(AlistClient): 使用属性方法装饰用户名和密码属性，避免被意外修改

app/api/alist/v3/client.py

@@ -37,8 +37,8 @@ def __init__(self, url: str, username: str, password: str) -> None:
             url = "https://" + url
         self.url = url.rstrip("/")
 
-        self.username = str(username)
-        self.__password = str(password)
+        self.__username = str(username)
+        self.___password = str(password)
         self.__dir = "/"
         self.__token = {
             "token": "",  # 令牌 token str
@@ -56,6 +56,22 @@ async def __aenter__(self):
     async def __aexit__(self, *_):
         await self.__session.close()
 
+    @property
+    def username(self) -> str:
+        """
+        获取用户名
+        """
+
+        return self.__username
+
+    @property
+    def __password(self) -> str:
+        """
+        获取密码
+        """
+
+        return self.___password
+
     @property
     def __get_token(self) -> str:
         """