feat: Replace Python IO with Rust FFI

[samuelburnham]

This PR replaces Python IO calls with faster/safer Rust FFI using https://docs.rs/revm-precompile/32.1.0/revm_precompile/ for the Rust backend and https://github.com/argumentcomputer/lean-ffi for a safe API over rust-bindgen bindings to the lean.h C library.

If this approach is of interest, we can replace the rest of the Python calls with FFI to https://github.com/bluealloy/revm.

I wasn't sure if Python or C was being used for blake2, Sha256, and Keccak, so I replaced both blake2 Python and C with Rust as a proof of concept for now. There is less benefit to replacing C with Rust, but the latter still produces simpler/less error-prone code. The Rust API has typed wrappers to distinguish owned from borrowed Lean references, and Clone/Drop implementations handle ref counting automatically instead of requiring manual lean_inc/lean_dec calls.

I also added a small test filtering helper to run e.g. just ripemd tests with

  lake exe conform \
    static_CallRipemd160_1_d0g0v0_Cancun \
    static_CallRipemd160_2_d0g0v0_Cancun \
    static_CallRipemd160_3_d0g0v0_Cancun \
    CALLCODERipemd160_0_d0g0v0_Cancun

where the test names were grepped from the Ethereum tests JSONs such as static_CallRipemd160_1.json.