Adds EntitySet { All, IndoorOnly, OutdoorOnly } and a Draw parameter to
partition the per-entity walk by ParentCellId presence. EntitySet.All
preserves pre-A8 behavior; IndoorOnly drops null-ParentCellId entities;
OutdoorOnly drops ParentCellId.HasValue entities. The visibleCellIds
filter is still applied on top.
Used by Task 7 to split the render frame's single Draw call into two
(indoor stencil-OFF, outdoor stencil-gated).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
