46625d247a
Outcome::Scored becomes a struct variant with an Option<f64> sigma field. None inherits HistoryBuilder::score_sigma; Some(s) overrides per event. Resolved at ingest time so EventKind::Scored stays a plain f64 and TimeSlice/run_chain need zero changes. New constructors Outcome::scores_with_sigma and EventBuilder::scores_with_sigma cover the override path; existing scores(..) keeps its signature with sigma=None internally. Breaking change to Outcome::Scored variant shape (tuple → struct); acceptable in 0.1.x. Closes the last item from the T4-MarginFactor deferred wishlist.