The occurrence's quantity sets, WITH mutations applied when present. A
mutationView built for a server-hydrated store (no quantity extractor,
!hasQuantityBase()) answers getQuantitiesForEntity from its overlay
ALONE, which would otherwise make an edited quantity's siblings — or an
untouched quantity set — vanish from a selector's reads; merge the base
back in for that case instead of trusting the overlay as the whole set.
The occurrence's quantity sets, WITH mutations applied when present. A
mutationViewbuilt for a server-hydrated store (no quantity extractor,!hasQuantityBase()) answersgetQuantitiesForEntityfrom its overlay ALONE, which would otherwise make an edited quantity's siblings — or an untouched quantity set — vanish from a selector's reads; merge the base back in for that case instead of trusting the overlay as the whole set.