test(render): Phase W Stage 4/5 — assembler OutsideView AABB + PView BFS + entity-clip tests

ClipFrameAssemblerTests (3 new):
- Assemble_OutsideViewWithExitPortal_HasOutsideViewTrue_AabbMatchesBounds
- Assemble_OutsideViewMultiPolygon_ScissorMode_HasOutsideViewTrue_AabbValid
- Assemble_EmptyOutsideView_HasOutsideViewFalse_AabbZero

PortalVisibilityBuilderTests (3 new):
- Build_ExitPortalVisible_OutsideViewNonEmpty
- Build_NoExitPortal_OutsideViewEmpty
- Build_RootCellAlwaysFirstInOrderedVisibleCells

EntityClipTests (new file, 5 tests):
- EntityClip_ParentInVisibleSet_Included
- EntityClip_ParentNotInVisibleSet_Excluded
- EntityClip_NullVisibleSet_IncludesAll
- EntityClip_NullParentCell_NullVisibleSet_Included
- EntityClip_NullParentCell_NonNullVisibleSet_Included

WbDrawDispatcher.EntityPassesVisibleCellGate changed private → internal static
(AcDream.App already has InternalsVisibleTo AcDream.App.Tests; no new seam needed).

160 → 171 tests, all green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/AcDream.App.Tests/Rendering/EntityClipTests.cs

@@ -0,0 +1,101 @@
+// EntityClipTests.cs
+//
+// Phase W Stage 4/5: unit-test WbDrawDispatcher.EntityPassesVisibleCellGate.
+// The gate is internal static (AcDream.App is InternalsVisibleTo AcDream.App.Tests)
+// and pure — tests it without a GL context. Covers: ParentCellId in the visible
+// set → included; ParentCellId NOT in the set → excluded; null visibleCellIds →
+// everything included (outdoor / unconstrained root).
+using System.Collections.Generic;
+using System.Numerics;
+using AcDream.App.Rendering.Wb;
+using AcDream.Core.World;
+using Xunit;
+
+namespace AcDream.App.Tests.Rendering;
+
+public sealed class EntityClipTests
+{
+    // Minimal WorldEntity factory. EntityPassesVisibleCellGate only reads
+    // ParentCellId and IsBuildingShell/BuildingShellAnchorCellId from the entity;
+    // the other required fields are set to safe sentinel values.
+    private static WorldEntity Entity(uint? parentCellId, bool isShell = false, uint? shellAnchor = null) =>
+        new WorldEntity
+        {
+            Id = 1u,
+            SourceGfxObjOrSetupId = 0u,
+            Position = Vector3.Zero,
+            Rotation = Quaternion.Identity,
+            MeshRefs = System.Array.Empty<MeshRef>(),
+            ParentCellId = parentCellId,
+            IsBuildingShell = isShell,
+            BuildingShellAnchorCellId = shellAnchor,
+        };
+
+    [Fact]
+    public void EntityClip_ParentInVisibleSet_Included()
+    {
+        // Entity whose ParentCellId is in the visible set must pass the gate.
+        const uint cellId = 0xA9B40170u;
+        var visibleCellIds = new HashSet<uint> { cellId };
+        var entity = Entity(parentCellId: cellId);
+
+        bool result = WbDrawDispatcher.EntityPassesVisibleCellGate(
+            entity, visibleCellIds, WbDrawDispatcher.EntitySet.All);
+
+        Assert.True(result);
+    }
+
+    [Fact]
+    public void EntityClip_ParentNotInVisibleSet_Excluded()
+    {
+        // Entity whose ParentCellId is NOT in the visible set must fail the gate.
+        const uint visibleCell = 0xA9B40170u;
+        const uint entityCell = 0xA9B40172u;
+        var visibleCellIds = new HashSet<uint> { visibleCell };
+        var entity = Entity(parentCellId: entityCell);
+
+        bool result = WbDrawDispatcher.EntityPassesVisibleCellGate(
+            entity, visibleCellIds, WbDrawDispatcher.EntitySet.All);
+
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void EntityClip_NullVisibleSet_IncludesAll()
+    {
+        // Null visibleCellIds means the outdoor root — no culling, all entities pass.
+        var entity = Entity(parentCellId: 0xA9B40172u);
+
+        bool result = WbDrawDispatcher.EntityPassesVisibleCellGate(
+            entity, visibleCellIds: null, WbDrawDispatcher.EntitySet.All);
+
+        Assert.True(result);
+    }
+
+    [Fact]
+    public void EntityClip_NullParentCell_NullVisibleSet_Included()
+    {
+        // An outdoor entity (ParentCellId == null) with null visibleCellIds passes.
+        var entity = Entity(parentCellId: null);
+
+        bool result = WbDrawDispatcher.EntityPassesVisibleCellGate(
+            entity, visibleCellIds: null, WbDrawDispatcher.EntitySet.All);
+
+        Assert.True(result);
+    }
+
+    [Fact]
+    public void EntityClip_NullParentCell_NonNullVisibleSet_Included()
+    {
+        // An outdoor entity (ParentCellId == null) with a non-null visibleCellIds
+        // falls through to the final return-true (not a shell, not shell-scoped);
+        // outdoor scenery is not gated by the indoor cell filter.
+        var visibleCellIds = new HashSet<uint> { 0xA9B40170u };
+        var entity = Entity(parentCellId: null);
+
+        bool result = WbDrawDispatcher.EntityPassesVisibleCellGate(
+            entity, visibleCellIds, WbDrawDispatcher.EntitySet.All);
+
+        Assert.True(result);
+    }
+}