[Feature] rocCV + MIGraphX classification sample

[zacharyvincze]

Description

This PR adds an MIGraphX image classification sample to demonstrate interoperability between rocCV (as the image preprocessor) and MIGraphX as the inference engine. Also in this PR are some quality of life improvements to the Python bindings.

Technical Details

Sample Application

• Added rocCV + MIGraphX Python image classification sample.

Changes to Python Bindings

• Swapped dtype and layout in rocpycv.Tensor constructors to match existing computer vision libraries.
• dtype parameters now accept numpy scalar types (e.g. np.uint8).
• layout parameters now accept string representations (e.g. "NHWC").
• Underlying tensor address can now be exposed using rocpycv.Tensor.data_ptr() to facilitate interoperability with other ROCm libraries such as MIGraphX.
• Underlying hipStream_t reference can now be exposed using rocpycv.Stream.handle().
• General improvements to documentation and the python stubs.

[Copilot]

Pull request overview

Adds a GPU image-classification sample demonstrating rocCV preprocessing feeding directly into MIGraphX (zero-copy via raw GPU pointer + shared HIP stream), alongside Python-binding ergonomics improvements (dtype/layout flexibility, interop helpers) and corresponding Python test updates.

Changes:

• Added new Python classification samples: MIGraphX (ONNX) and PyTorch (ResNet50).
• Updated Python bindings to accept NumPy dtypes and layout strings, reordered Tensor ctor args, and exposed Tensor.data_ptr() + Stream.handle().
• Updated existing Python operator tests to use the new Tensor constructor argument order.

Reviewed changes

Copilot reviewed 34 out of 36 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tests/roccv/python/test_op_warp_perspective.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_warp_affine.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_thresholding.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_rotate.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_resize.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_remap.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_reformat.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_normalize.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_non_max_suppression.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_histogram.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_gamma_contrast.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_flip.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_cvt_color.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_custom_crop.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_copy_make_border.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_convert_to.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_composite.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_center_crop.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_bnd_box.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_bilateral_filter.py	Update Tensor(...) ctor arg order in test.
tests/roccv/python/test_op_adv_cvt_color.py	Update Tensor(...) ctor arg order in test.
samples/pytorch-classification/pytorch_classification.py	New sample: rocCV preprocessing + PyTorch inference.
samples/pytorch-classification/README.md	Docs for the PyTorch sample.
samples/migraphx-classification/migraphx_classification.py	New sample: rocCV preprocessing + MIGraphX inference, zero-copy buffer + shared stream.
samples/migraphx-classification/README.md	Docs for MIGraphX sample usage + interop details.
python/src/rocpycv.pyi	Updated stubs/docs, new interop methods, relaxed dtype/layout typing.
python/src/py_tensor.cpp	Reordered ctor args; accept NumPy dtype/layout strings; add data_ptr; update reshape/from_dlpack to accept layout strings.
python/src/py_stream.cpp	Add Stream.handle() returning hipStream_t as integer.
python/src/py_helpers.cpp	Add LayoutFromPyObject / DataTypeFromPyObject parsing helpers.
python/src/py_enums.cpp	Adjust exported Python enums (notably eDataType).
python/src/operators/py_op_reformat.cpp	Allow reformat(..., out_layout) to accept layout strings.
python/src/operators/py_op_convert_to.cpp	Allow convert_to(..., dtype) to accept NumPy dtype/scalar types.
python/src/main.cpp	Expanded module docstring/quick-start documentation.
python/include/py_tensor.hpp	Match ctor arg reorder; declare getDataPtr.
python/include/py_stream.hpp	Declare getHandle.
python/include/py_helpers.hpp	Declare new dtype/layout parsing helpers.

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[zacharyvincze]

Added additional tests for PyStream/PyTensor since they've added functionality.