docs: add README

README.md

@@ -1,3 +1,27 @@
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 license: apache-2.0
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+
+# Introduction
+
+This repository hosts the [RFDetr](https://github.com/roboflow/rf-detr) keypoint
+(pose) model for pose estimation for the [React Native
+ExecuTorch](https://www.npmjs.com/package/react-native-executorch) library. It
+includes models exported using XNNPack, CoreML and MLX backends in `.pte` format,
+ready for use in the **ExecuTorch** runtime.
+
+If you'd like to run these models in your own ExecuTorch runtime, refer to the
+[official documentation](https://pytorch.org/executorch/stable/index.html) for
+setup instructions.
+
+# Compatibility
+
+If you intend to use these models outside of React Native ExecuTorch, make sure
+your runtime is compatible with the ExecuTorch version used to export the `.pte`
+files. For more details, see the compatibility note in the ExecuTorch GitHub
+repository. If you work with React Native ExecuTorch, the constants from the
+library will guarantee compatibility with runtime used behind the scenes.
+
+These models were exported using **ExecuTorch** version 1.3.0 and no forward
+compatibility is guaranteed. Older versions of the runtime may not work with
+these files.