fix path exists error

utils/download_weights.py

@@ -16,7 +16,7 @@ def download_weights():
     checkpoint_dir = Path.home() / ".foundry" / "checkpoints"
     for model in MODELS:
         model_path = os.path.join(checkpoint_dir, model+".ckpt")
-        if model_path.exists():
+        if os.path.exists(model_path):
             print(f"{model} already exists at {model_path}, skipping download.")
         else:
             cmd = f"foundry install {model} --checkpoint-dir {checkpoint_dir}"