Fix deprecated langchain imports

vectorstore/pinecone_delta_upsert.py

@@ -117,7 +117,7 @@ def chunk_bill(bill: Dict[str, Any], size: int = 1500, overlap: int = 200) -> Li
     Includes numeric fields: session_year_start, session_year_end, last_action_ts (epoch seconds).
     Stores iapp_flat as list[str] for Pinecone $in filters.
     """
-    from langchain.text_splitter import RecursiveCharacterTextSplitter
+    from langchain_text_splitters import RecursiveCharacterTextSplitter
 
     doc_id = f"{bill.get('state','Unknown')}_{bill.get('bill_number','Unknown')}"
     title = bill.get("title") or ""