Errors
Semantic error types mapped to exit codes by the top-level runner.
Decisions
byob-errors.1— Semantic error types and a FlagErrorf helper; top-level runner maps them to exit codesbyob-errors.2— Attachable ErrHint wrapper carries remediation textbyob-errors.4— SilenceUsage and SilenceErrors on the root commandbyob-errors.5— Function signatures return `error`, not the concrete error type