Rust preset

A reasoning guide the onboard flow uses for Rust projects. It is a checklist, not a template — detected reality wins.

Signals

• Cargo.toml and Cargo.lock; a src/main.rs (binary) or src/lib.rs (library), with modules under src/.
• A [workspace] with members for multi-crate monorepos; [features] for optional capabilities.

What to reason about

• The real gate: cargo test, cargo clippy (often -- -D warnings), cargo fmt --check, and cargo build --release — captured verbatim.
• Crate type (binary vs library), the module tree, and which features are default vs optional.
• Stack-appropriate skills for modules, error types, and integration vs unit tests (inline #[cfg(test)] vs tests/).

Notes

For workspaces, capture per-crate boundaries and which crate owns the binary. Note any build.rs, MSRV, or unsafe boundaries.