SpannedValue<T> is a generic wrapper that captures the TOML byte span location of a parsed value. It enables precise error messages pointing to the exact source location, making it reusable for any TOML-based configuration system that needs high-quality diagnostics. The implementation is self-contained and depends only on standard traits (AsRef, Deref, Serialize, Deserialize).

Implements Jaro-Winkler distance-based 'did you mean?' suggestions for mistyped identifiers. It can be extracted and used in any CLI or library that needs to suggest valid alternatives from a list. Accepts an iterator of valid names and returns ranked matches with similarity scores.

Provides a reusable interactive yes/no prompt with configurable timeout, default answer, and message. Wraps the demand library but abstracts platform-specific TTY handling. Can be extracted for any CLI that needs to confirm sensitive operations with a timeout guarantee.

Abstracts OS-level credential stores (macOS Keychain, Windows Credential Manager, Linux Secret Service) behind a uniform async interface. Uses spawn_blocking to avoid runtime deadlocks with blocking keyring APIs. The pattern of wrapping synchronous system APIs with blocking pool spawn is reusable for any Rust async application dealing with platform-specific secure storage.