standardize .env loading behavior across modules

lightrag/lightrag.py

@@ -55,8 +55,10 @@ from .utils import (
 from .types import KnowledgeGraph
 from dotenv import load_dotenv
 
-# Load environment variables
-load_dotenv(override=True)
+# use the .env that is inside the current folder
+# allows to use different .env file for each lightrag instance
+# the OS environment variables take precedence over the .env file
+load_dotenv(dotenv_path=".env", override=False)
 
 # TODO: TO REMOVE @Yannick
 config = configparser.ConfigParser()