#1058 Public workflow error reports max_attempts from the run budget, not the failing step's retry budget

EARS SPEC: - When a step fails, the public workflow error shall report attempts and max_attempts of that step (its RetryPolicy, or 1 without one). EVIDENCE (#1056 demo matrix): retry_exhausted (RetryPolicy max_retries=2) shows attempts=3, max_attempts=5; verify_join (no retry policy) also shows max_attempts=5. engine/orchestrator/public_error.py takes attempts from the step message but max_attempts from the orchestrator run budget (failure_handler.py). Misleads audit of failures. SYNTHESIS: localized bugfix; domain = error reporting; concept = report the step's own retry budget.