Update app.py

app.py

@@ -56,6 +56,7 @@ st.title("📄 Chat with Your PDF")
 
 # 1) Ingest once or load existing index via index_store.json
 if "index_ready" not in st.session_state:
+    os.makedirs(INDEX_DIR, exist_ok=True)  # ensure folder exists
     index_meta = os.path.join(INDEX_DIR, "index_store.json")
     if os.path.isfile(index_meta):
         # Found LlamaIndex metadata → reuse existing index