Rust review

Review Rust code against the same rules the rust-best-practices skill uses for writing it, and report what to change. The output is a review, not a rewrite: the reader decides what to fix. Only rewrite code when the user asks for that.

1. Decide the scope

• What to read. Review exactly what the user pointed at: a file, a module, a crate, or a diff. For a diff, review the changed lines and anything they break, not the whole file.
• Library or application. Check for a lib.rs, pub items used by other crates, or a published Cargo.toml. Library code is held to the API-design rules strictly. Application code gets the simplicity rules instead: concrete types, anyhow-style errors, and no speculative generality. Say which you assumed at the top of the report.
• The edition and MSRV, from Cargo.toml, so you don't recommend features the project can't use.

2. Run the tools first, if you can