- public API streamline - Failf[T]("msg") - originate a failure from a message; embed a cause with %w - Err[T](err) - sets .err verbatim (the return zero, err / sentinel case)
- wrap existing errors with context + file:line, newline-separated for readable error chains - dual mode philosophy: panics + if err != nil - unify Expect for goexit and panic cases
