optimize sql

[mitchelljkotler]

querysets.py

• Replaced EntitlementGrantQuerySet.matching() (Python loop + matches() call + N hidden queries) with for_org() — a pure SQL method that expresses all matching logic as Q objects using the org's known scalar attributes.
• Rewrote EntitlementQuerySet.for_organization() to pass the lazy for_org() queryset directly as a subquery instead of materializing grant PKs with [g.pk for g in ...].

serializers.py

• Added from django.db.models import Q.
• Rewrote get_entitlements() to compute matching_grants = EntitlementGrant.objects.for_org(obj) once, use it in the Entitlement.objects.filter(...) query, and iterate it again (with prefetch_related("entitlements")) for the grant_update_on map — eliminating the second
  call to matching().

tasks.py

• Replaced the for grant in ... N+1 loop in restore_organization() with collecting querysets per grant and merging them via .union(), so all matching-org lookups go through one SQL UNION query instead of N separate queries.