Initial project import

CONTRIBUTING.md

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+# Contributing
+
+Contributions should be small, portable, documented, and independently written for AGX Open.
+
+- Do not submit proprietary AGX Engine code.
+- Do not include credentials, private endpoints, customer data, or internal documents.
+- Add or update an example when changing a public API.
+- Run `make test` before opening a pull request.
+- Keep the CPU reference backend understandable for students.