Lightweight, user-facing methods for engine configuration objects (class `nmar_engine`). These improve discoverability and provide a consistent print surface across engines while keeping the objects as simple lists internally.
Design
- `engine_name()` returns a canonical identifier used across the package (e.g., in `nmar_result$meta$engine_name`). - `print.nmar_engine()` provides a concise, readable summary of the engine configuration; engine-specific classes reuse the parent method unless they need to override it. - `engine_config()` returns the underlying configuration as a named list for programmatic inspection.