Version Delta

A visual of how a metric changed from the previous version of THIS resource — the same canonical key at the highest version below the current. `metricPath` is the value to compare; the band draws a 0..1 track marking the prior and current values, colored by direction, with a delta badge and a "vs {version}" label. Pairs with a prose band (e.g. a confidenceRationale Markdown) that explains the why.