T2 slice 3 (BR-4): draw-driven flood gating - per-building frustum pre-gate, 48m seed cap DELETED

Retail floods a building's interior exactly when its shell DRAWS and an
aperture survives the view: DrawBuilding (Ghidra 0x0059f2a0) -> per-view
viewconeCheck on the shell -> portal-BSP walk -> ConstructView(CBldPortal)
side test + GetClip-vs-view + GetVisible. There is NO distance constant
anywhere on that chain (verifier-confirmed, flood-gate-shape adjusted).

Port:
- GameWindow's outdoor-node gather: per-BUILDING frustum pre-gate on the
  aperture bounds (Building.PortalBounds - the tight flood-purposes
  equivalent of the shell viewconeCheck), iterating the per-landblock
  BuildingRegistries. Replaces the Chebyshev<=1 landblock cell-sweep.
  Also the proper fix for the 2026-06-07 'FPS drops when I look out'
  problem the Chebyshev hack approximated: dozens of AABB tests instead
  of an O(all loaded cells) portal sweep.
- OutdoorBuildingSeedDistance 48f -> infinity (the binary visibility pop
  at ~48 m - the confirmed #109 mechanism candidate - is gone; admission
  is now the screen clip per portal, retail's GetClip gate).
- The legacy clipRoot==null look-in path keeps its 48 m: it is T4
  deletion scope; improving doomed code wastes effort.

Closes the building-flood-seeding-48m-cutoff divergence (culling area,
adjusted-confirmed). Suites: App 226 green (flood gates included).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Rendering/RetailPViewRenderer.cs

@@ -26,7 +26,13 @@ public sealed class RetailPViewRenderer
 
     // R-A2: per-building flood grouping, reused across frames (inner lists cleared each frame).
     private readonly Dictionary<uint, List<LoadedCell>> _buildingGroups = new();
-    private const float OutdoorBuildingSeedDistance = 48f;
+
+    // T2 (BR-4): retail has NO distance constant on the flood-admission chain
+    // (DrawBuilding → portal walk → ConstructView: viewconeCheck + side test +
+    // GetClip + GetVisible only). The old 48 m seed cap is replaced by the
+    // caller's per-building frustum pre-gate on aperture bounds (GameWindow's
+    // gather); seeds themselves are unbounded.
+    private const float OutdoorBuildingSeedDistance = float.PositiveInfinity;
 
     public RetailPViewRenderer(
         GL gl,