FittingRunner

Synchronous driver that turns one fit configuration into a serializable FitResultData by orchestrating the appropriate engine: PDFModeler for the continuous path and PMFModeler for the discrete path. It owns import and the estimate/score/evaluate sequence, and hands the live results to FitResultExtractor for translation into the DTO. The live engine objects are used only transiently and are never exposed — presentation is driven entirely from the returned DTO (plus the caller's own raw data for plots).

This runner does no event emission, no validation, and no async control: the async session wraps it in a coroutine and converts thrown exceptions into a typed failure result.