Portable exit status primitives for `RustUse` CLI-adjacent code.
`use-exit-code` keeps common process exit meanings explicit while staying small and platform-aware.
```rust
use use_exit_code::{CONFIG_ERROR, ExitCode, SUCCESS};
let success = ExitCode::from_u8(0);
assert_eq!(success, SUCCESS);
assert_eq!(CONFIG_ERROR.as_i32(), 78);
```
This crate does not spawn processes, inspect child status values, or manage application shutdown.