Push the boolean and date custom-field predicates and custom-field
sorting down to JSONB expressions so the overview stops classifying
custom-field values in memory. A GIN index on custom_field_values.value
keeps the boolean membership predicates index-served.
- Authorizer and policies: bypass for read (member_id == actor.member_id),
CustomFieldValueCreateScope for create, HasPermission for read/update/destroy.
- HasPermission: pass authorizer into strict_check helper; document that create
must use a dedicated check (no filter).
