CRITICAL FIX: Pass ckpt_path to build_sam3_image_model() to prevent internal download hang without HF token

app.py

@@ -85,12 +85,10 @@ processor = None
 
 if model_installed:
     print(f"Loading SAM 3 onto {device}...")
-    model = build_sam3_image_model()
-    # NOTE: build_sam3_image_model() already loads checkpoint weights internally
-    # via _load_checkpoint(). DO NOT load the checkpoint again manually—it corrupts
-    # the weights with incorrect key mappings and causes zero masks!
-    model.to(device)
-    model.to(torch.float32)  # Lossless 32-bit execution prevents BFloat16 exponent overflows (NaNs)
+    model = build_sam3_image_model(checkpoint_path=ckpt_path)
+    # NOTE: build_sam3_image_model() internally loads weights, remaps keys,
+    # and calls model.cuda().eval(). We just need to cast to float32 for T4.
+    model.to(torch.float32)
         
     processor = Sam3Processor(model)
     if not torch.cuda.is_available():