rust-executable-specs-01

@that-in-rust

Unify executable specifications, idiomatic Rust architecture, and reliability-first Rust delivery for libraries, CLIs, async services, app backends, and contained FFI wrappers. Use when Codex needs to decide how to approach Rust work, convert requests into REQ-RUST contracts, choose L1/L2/L3 boundaries, apply typed-error and async/concurrency safety patterns, select verification strategy, enforce four-word naming where feasible, or produce quality gates and implementation plans.