Update app.py

app.py

@@ -22,7 +22,7 @@ from groq import Groq
 from pypdf import PdfReader
 from sentence_transformers import SentenceTransformer
 from sklearn.feature_extraction.text import TfidfVectorizer
-
+from pathlib import Path
 
 # ══════════════════════════════════════════════════════════
 #  RAG 核心邏輯（優化版）