Thread the new createPersistentStore.destroy() through its owners so the
save effect.root is actually torn down: LayoutManager gains destroy();
ThemeManager and typographySettings dispose their #store in their existing
destroy().
comparisonStore had its own leak — a constructor $effect.root whose disposer
was discarded, and a module-level persistent storage created at import. Move
storage into the instance (#storage, created lazily per instance), capture
the effect.root disposer, add destroy(), and adopt createSingleton so reset
runs resetAll() + destroy(). Re-export createSingleton from the $shared/lib
barrel; give the test storage mock a destroy().
Ilia Mashkov
0aae710e35