refactor: update Document import from `langchain.schema` to `langchain_core.documents` and adjust dependencies.

data_cutter.py

@@ -1,6 +1,6 @@
 import os
 import pdfplumber
-from langchain.schema import Document
+from langchain_core.documents import Document
 from langchain_text_splitters import RecursiveCharacterTextSplitter
 from langchain_huggingface import HuggingFaceEmbeddings
 from langchain_chroma import Chroma

requirements.txt

@@ -1,5 +1,6 @@
 pdfplumber
 langchain
+langchain-core
 langchain-chroma
 langchain-text-splitters
 langchain-huggingface