fix: Correct pointer dereference in NamedTensors.__setitem__

Fixed segfault in test_NamedTensors caused by incorrect pointer handling.

Issue:
- ToOgaTensor() returns std::unique_ptr<OgaPy::OgaTensor>
- tensor.get() returns OgaPy::OgaTensor* (wrapper class pointer)
- We need tensor->get() to get the inner C API OgaTensor* pointer

The reinterpret_cast was treating a wrapper pointer as a C API pointer,
causing invalid memory access and segfault.

Tested locally - NamedTensors now works correctly.

Author: ONNX GenAI Assistant

src/python/python.cpp

@@ -403,7 +403,7 @@ NB_MODULE(onnxruntime_genai, m) {
       })
       .def("__setitem__", [](OgaPy::OgaNamedTensors& named_tensors, const std::string& name, nb::ndarray<>& value) {
         auto tensor = ToOgaTensor(value);
-        OgaPy::OgaCheckResult(OgaNamedTensorsSet(named_tensors.get(), name.c_str(), reinterpret_cast<OgaTensor*>(tensor.get())));
+        OgaPy::OgaCheckResult(OgaNamedTensorsSet(named_tensors.get(), name.c_str(), tensor->get()));
       })
       .def("__setitem__", [](OgaPy::OgaNamedTensors& named_tensors, const std::string& name, OgaPy::OgaTensor& value) {
         OgaPy::OgaCheckResult(OgaNamedTensorsSet(named_tensors.get(), name.c_str(), value.get()));