onRelease property
Called when the gesture ends with a ReleaseContext — raw end-state
inputs. Consumer calls Stage.of(context).release(Release.toDisplay(data))
for the default plan, or builds a custom plan and calls .run(...) /
.backToOrigin(data) / etc.
Cascade fallback when null: DisplayConfig.onRelease → Origin.onRelease / Stage.onRelease → package default.
Implementation
final OnRelease? onRelease;