feat: 重构数据库导入路径，移除旧的数据库模块并添加新的数据库实现

src/common/database/database.py

@@ -0,0 +1,60 @@
+import os
+from pymongo import MongoClient
+from pymongo.database import Database
+from rich.traceback import install
+
+install(extra_lines=3)
+
+_client = None
+_db = None
+
+
+def __create_database_instance():
+    uri = os.getenv("MONGODB_URI")
+    host = os.getenv("MONGODB_HOST", "127.0.0.1")
+    port = int(os.getenv("MONGODB_PORT", "27017"))
+    # db_name 变量在创建连接时不需要，在获取数据库实例时才使用
+    username = os.getenv("MONGODB_USERNAME")
+    password = os.getenv("MONGODB_PASSWORD")
+    auth_source = os.getenv("MONGODB_AUTH_SOURCE")
+
+    if uri:
+        # 支持标准mongodb://和mongodb+srv://连接字符串
+        if uri.startswith(("mongodb://", "mongodb+srv://")):
+            return MongoClient(uri)
+        else:
+            raise ValueError(
+                "Invalid MongoDB URI format. URI must start with 'mongodb://' or 'mongodb+srv://'. "
+                "For MongoDB Atlas, use 'mongodb+srv://' format. "
+                "See: https://www.mongodb.com/docs/manual/reference/connection-string/"
+            )
+
+    if username and password:
+        # 如果有用户名和密码，使用认证连接
+        return MongoClient(host, port, username=username, password=password, authSource=auth_source)
+
+    # 否则使用无认证连接
+    return MongoClient(host, port)
+
+
+def get_db():
+    """获取数据库连接实例，延迟初始化。"""
+    global _client, _db
+    if _client is None:
+        _client = __create_database_instance()
+        _db = _client[os.getenv("DATABASE_NAME", "MegBot")]
+    return _db
+
+
+class DBWrapper:
+    """数据库代理类，保持接口兼容性同时实现懒加载。"""
+
+    def __getattr__(self, name):
+        return getattr(get_db(), name)
+
+    def __getitem__(self, key):
+        return get_db()[key]
+
+
+# 全局数据库访问点
+db: Database = DBWrapper()