feat(render): Phase A8 — indoor visibility + streaming fixes batch

Lands the working A8 indoor-rendering and streaming fixes accumulated this
session. User has verified these visually to some degree (e.g. lifestone /
translucent meshes confirmed fine under the FrontFace flip; bridge / wall /
collision regressions confirmed fixed after travel); not every path has been
exhaustively gated. The cellar-flap defect remains OPEN and will be solved
the retail-faithful way via a dedicated brainstorm (see handoff docs).

Rendering core (reviewed, high confidence):
- EnvCellRenderer SSBO stride fix: upload packed Matrix4x4[] (64B) instead of
  the 80B CPU InstanceData struct the shader never expected — fixes the
  transform/texture "explosion" for any draw with >1 instance (cells that
  dedupe to a shared cellGeomId). Real root cause.
- WB-style global FrontFace(CW) + per-batch CullMode carried through the MDI
  layout (GroupKey + BuildIndirectArrays + DrawIndirectRange split into
  same-cull runs with absolute uDrawIDOffset per run).
- EntitySet partitioning (IndoorPass / OutdoorScenery / LiveDynamic) +
  WorldEntity.BuildingShellAnchorCellId so building shells scope to their
  dat-derived building cell instead of rendering everywhere.
- RenderOutsideInAcdream (look into buildings from outside) +
  CollectVisiblePortalBuildings frustum cull of portal bounds.
- Sky-when-inside-building + per-cell audit probe + GL-state probe.

Streaming / perf (test-covered; not independently code-reviewed this session):
- Near/far priority queues so near work wins over far; PromoteToNear carries
  full landblock + mesh data; LandblockEntriesWithoutAnimatedIndex avoids
  rebuilding the animated-lookup dict in the hot draw path. Fixes the
  bridge-not-appearing / missing-walls / broken-collision-after-travel
  regressions and improves post-transition FPS.

Tooling + docs:
- tools/A8CellAudit: offline dat cell/portal/building dumper (portals +
  buildings modes) — reproduces the cellar-flap investigation with no launch.
- docs/research cellar-flap root-cause + option-2 handoff (the didInsideStencil
  double-duty finding + the WB-recursive design decision + brainstorm prompt),
  entity-taxonomy, replan, issue-78 visibility investigation.

Diagnostics retained on purpose: ACDREAM_A8_DIAG_* gates, portal_stencil.vert
provisional pos.w clamp, and the probe families are kept (env-var gated, zero
cost when off) because the pending option-2 cellar-flap brainstorm needs them.
Strip in the option-2 ship commit.

Indoor branch stays behind ACDREAM_A8_INDOOR_BRANCH=1 (default off = pre-A8
visual). Build green; App tests + Core (streaming/dispatcher/loader) tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.App/Rendering/Wb/Building.cs

@@ -6,10 +6,9 @@ namespace AcDream.App.Rendering.Wb;
 /// <summary>
 /// Phase A8 (2026-05-26): a logical building — one or more EnvCells linked
 /// via the dat-level <c>LandBlockInfo.Buildings</c> entry. Building shells (cottage
-/// walls, inn walls — <c>IsBuildingShell=true</c> entities) render unconditionally
-/// when the camera is inside this building's cells. The exit portal polygons
-/// are stencil-marked so outdoor visibility leaks through portal silhouettes
-/// only.
+/// walls, inn walls — <c>IsBuildingShell=true</c> entities) are scoped to this
+/// building's cells via their dat-derived anchor. The exit portal polygons are
+/// stencil-marked so outdoor visibility leaks through portal silhouettes only.
 ///
 /// <para>Step 5 (cross-building visibility via 3-stencil-bit pipeline) uses
 /// the occlusion-query state to skip rendering when the building's portals
@@ -39,6 +38,18 @@ public sealed class Building
     /// polygon vertices via <see cref="AcDream.App.Rendering.LoadedCell.WorldTransform"/>.</summary>
     public required IReadOnlyList<Vector3[]> ExitPortalPolygons { get; init; }
 
+    /// <summary>True when <see cref="PortalBounds"/> contains at least one
+    /// exit-portal vertex. Mirrors WB's <c>BuildingPortalGPU.VertexCount &gt; 0</c>
+    /// filter before a building participates in outside-in / Step 5 stencil
+    /// visibility.</summary>
+    public bool HasPortalBounds { get; init; }
+
+    /// <summary>World-space AABB of all exit portal polygons. WB's
+    /// <c>PortalRenderManager.GetVisibleBuildingPortals</c> frustum-culls this
+    /// box with near-plane ignored before adding the building to the portal
+    /// visibility list.</summary>
+    public WbBoundingBox PortalBounds { get; init; }
+
     // -------------------------------------------------------------------------
     // Step 5 occlusion-query state (mutable, per-frame, RR9 scope).
     // -------------------------------------------------------------------------