[TE] Enhance Transfer Engine Rust library with CI tests and fixes (#3461)

* [TransferEngine] Add high-performance Rust library API

Promote transfer_engine_rust from an example binary to a library crate
that wraps transfer_engine_c.h. Hot-path types are #[repr(C)] and
layout-checked so submit_transfer passes slices to C with no Rust-side
allocation. Cover the full C ABI plus Python-shaped convenience
transfers, a page-aligned MemoryPool, CMake cargo targets, and docs.


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Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Teng Ma <stmatengss@users.noreply.github.com>