Initial commit: DCNv4 custom op mirror setup

- Add enhanced README with project structure and quick start guide
- Initialize repository with DCNv4 CUDA extension (PyTorch module)
- Include classification, detection, and segmentation subdirectories
- Reference upstream OpenGVLab DCNv4 implementation

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

classification/ops_dcnv3/src/vision.cpp

@@ -0,0 +1,17 @@
+/*!
+**************************************************************************************************
+* InternImage
+* Copyright (c) 2022 OpenGVLab
+* Licensed under The MIT License [see LICENSE for details]
+**************************************************************************************************
+* Modified from
+*https://github.com/chengdazhi/Deformable-Convolution-V2-PyTorch/tree/pytorch_1.0.0
+**************************************************************************************************
+*/
+
+#include "dcnv3.h"
+
+PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
+    m.def("dcnv3_forward", &dcnv3_forward, "dcnv3_forward");
+    m.def("dcnv3_backward", &dcnv3_backward, "dcnv3_backward");
+}