codex32 lean4 implementation

[stutxo]

Hey, i'm working (well my llm is) on a lean4 implementation of codex32, just for educational purposes really but maybe you will find it interesting.

https://github.com/stutxo/codex32_lean

I used just bip93 as the reference.

Also have some feedback for the bip here stutxo/codex32_lean#1

thanks!

[apoelstra]

Super cool! Thanks for vetting this stuff. Hopefully soon-ish we will have a new rust-bech32 release and can work on rewriting/fixing the Rust reference for the recent changes to the BIP.