Coding Guidelines

This gives Claude 50 core Rust conventions that go beyond what it already knows from training. It's meant for the non-obvious stuff: no get_ prefix on getters, when to use as_ versus to_ versus into_, why G_CONFIG for statics but no prefix for consts, and which crates have been deprecated by newer stdlib features (like OnceLock replacing lazy_static in 1.70). The tables are dense reference material, not tutorial content. Invoke this when you're doing code review, arguing about naming conventions, or wondering if there's a more idiomatic way to do something. It won't teach you Rust, but it will save you from bikeshedding and outdated patterns.