refactor(breadcrumb): relocate Breadcrumb slice from entities to features

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.

src/features/Breadcrumb/model/index.ts

@@ -0,0 +1,2 @@
+export * from './store/scrollBreadcrumbsStore.svelte';
+export * from './types/types.ts';