Fix DLPack: use frame.to_dlpack() for decord→CuPy zero-copy

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sexp_effects/primitive_libs/streaming_gpu.py

@@ -332,10 +332,11 @@ class GPUVideoSource:
 
             # Convert to CuPy via DLPack (zero-copy GPU transfer)
             if GPU_AVAILABLE:
-                # decord tensors support DLPack for zero-copy conversion
-                # This keeps the frame on GPU without any CPU transfer
+                # decord tensors have .to_dlpack() which returns a PyCapsule
+                # that CuPy can consume for zero-copy GPU transfer
                 try:
-                    gpu_frame = cp.from_dlpack(frame_tensor)
+                    dlpack_capsule = frame_tensor.to_dlpack()
+                    gpu_frame = cp.from_dlpack(dlpack_capsule)
                     # Log success once per source
                     if not getattr(self, '_dlpack_logged', False):
                         print(f"[GPUVideoSource] DLPack zero-copy SUCCESS - frames stay on GPU", file=sys.stderr)