Update app.py

app.py

@@ -39,7 +39,7 @@ def flatten_json(obj: dict) -> str:
 def load_vector_store(data_dir: str):
     texts = []
     for fname in os.listdir(data_dir):
-        if fname.lower().endswith('.json'):
+        if fname.lower().endswith('.md'):
             path = os.path.join(data_dir, fname)
             try:
                 with open(path, 'r', encoding='utf-8') as f: data = json.load(f)