standardize .env loading behavior across modules

lightrag/base.py

@@ -16,7 +16,10 @@ import numpy as np
 from .utils import EmbeddingFunc
 from .types import KnowledgeGraph
 
-load_dotenv()
+# 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)
 
 
 class TextChunkSchema(TypedDict):