Fix filter scoping for Home Screen Sections queries

[EclipseKnight]

I tracked this to the filter guard in GelatoItemRepository.ApplyFilters.

This regression appears tied to commit 1cb8d57 (refactor: filter out streams on everything except single item queries), which changed the guard to rely on IsSingleItemList().

The old check used !ctx.IsSingleItemList(), and IsSingleItemList() depends on this block in Common.cs:

var q = ctx.Request.Query;
if (!q.TryGetValue("ids", out var idsRaw))
    return false;

Home Screen Sections does not use ids for these calls, so those requests were treated like normal listings and got over-filtered, which resulted in slow loading and timeouts.

I changed the guard to ctx.IsApiListing() and added isSingleItemQuery = filter.ItemIds is { Length: 1 }. Filters now apply only when ctx.IsApiListing() && !isSingleItemQuery.

This keeps listing filters on real listing endpoints and fixes Home Screen Sections latest rows loading correctly.

[EclipseKnight]

Closing this in favor of #122, which consolidates the filter scope fix and the Home Screen Sections listing-action update in one PR.