Rust API Design guidelines, naming conventions, and best practices. Use when:
- User is designing a library, crate, or public APIs
- Implementing patterns like Builder, Typestate, or Extension traits
- Designing public structures, enums, or traits
- Working with common traits (From/Into, Default, AsRef, Debug, Clone)
- Applying #[must_use] or #[non_exhaustive] attributes
- Restricting trait implementation via Sealed Traits
- Formatting naming structures and lifetime designs
