mongodb支持配置用户名密码，向下兼容

src/common/database.py

@@ -4,18 +4,24 @@ from typing import Optional
 class Database:
     _instance: Optional["Database"] = None
     
-    def __init__(self, host: str, port: int, db_name: str):
-        self.client = MongoClient(host, port)
+    def __init__(self, host: str, port: int, db_name: str, username: Optional[str] = None, password: Optional[str] = None, auth_source: Optional[str] = None):
+        if username and password:
+            # 如果有用户名和密码，使用认证连接
+            # TODO: 复杂情况直接支持URI吧
+            self.client = MongoClient(host, port, username=username, password=password, authSource=auth_source)
+        else:
+            # 否则使用无认证连接
+            self.client = MongoClient(host, port)
         self.db = self.client[db_name]
         
     @classmethod
-    def initialize(cls, host: str, port: int, db_name: str) -> "Database":
+    def initialize(cls, host: str, port: int, db_name: str, username: Optional[str] = None, password: Optional[str] = None, auth_source: Optional[str] = None) -> "Database":
         if cls._instance is None:
-            cls._instance = cls(host, port, db_name)
+            cls._instance = cls(host, port, db_name, username, password, auth_source)
         return cls._instance
         
     @classmethod
     def get_instance(cls) -> "Database":
         if cls._instance is None:
             raise RuntimeError("Database not initialized")
-        return cls._instance 
+        return cls._instance