Convert the eager scrollBreadcrumbsStore singleton to getScrollBreadcrumbsStore()
(+ __resetScrollBreadcrumbsStore for tests) and add a public destroy() that
disconnects the IntersectionObserver and scroll listener. Update the feature
barrel and consumers (BreadcrumbHeader, BreadcrumbHeaderSeeded, NavigationWrapper).
Breadcrumb is not a business aggregate — it is a scroll-tracking navigation
capability (NavigationWrapper registers page sections into a store), so it
belongs in the features layer, not entities. Move the whole slice and
repoint its three widget consumers. entities/ now holds only Font, a true
aggregate.
Ilia Mashkov