GetBaseItemDtos already batch fetches user data, child counts, played counts
and artists before its per item loop, but AttachPeople still ran one GetPeople
query per item. Rendering a page of items (for example a large playlist) fired
one extra query per row.
Add GetPeopleByItems to IPeopleRepository, which reads every requested item in a
single query over the people mapping table and returns full PersonInfo (role,
type and sort order) grouped by item id. GetBaseItemDtos prefetches this once
when the People field is requested and passes it into AttachPeople, which reads
from the batch instead of querying per item. The single item GetBaseItemDto path
keeps its existing per item behaviour when no batch is supplied.
Adds a DtoService test asserting people resolve from the batch and the per item
GetPeople is never called.
This patch fixes issue #16032 where the Playlists media folder ignored a user-uploaded Primary image and kept showing the generated collage. The root cause was DTO image precedence on UserView items for CollectionType.playlists. We now prefer the display parent (PlaylistsFolder) Primary image when available by clearing the UserView Primary tag and setting ParentPrimaryImageItemId/ParentPrimaryImageTag. Added tests cover both paths: parent custom image preferred, and fallback to existing UserView Primary when parent has none.
brandon