force 0.3+ langchain wheels

rag.py

@@ -1,4 +1,4 @@
-# rag.py  (v6 – imports that exist in 0.3+ wheels)
+# rag.py  (v7 – imports that exist in 0.3+ wheels)
 from __future__ import annotations
 import os, uuid, tempfile, requests, shutil, re
 from pathlib import Path

requirements.txt

@@ -1,11 +1,10 @@
 flask
-langchain
-langchain-core
-langchain-community
-langchain-huggingface
+langchain>=0.3.0
+langchain-community>=0.3.0
+langchain-huggingface>=0.3.0
 sentence-transformers
 faiss-cpu
 datasets
-supabase
+supabase>=2.6
 python-dotenv
 gunicorn