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/ClipFrameAssemblerTests.cs

@@ -159,6 +159,80 @@ public class ClipFrameAssemblerTests
         Assert.Equal(TerrainClipMode.Planes, asm.TerrainMode);
     }
 
+    // -----------------------------------------------------------------------
+    // Phase W Stage 4: HasOutsideView + OutsideViewNdcAabb
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void Assemble_OutsideViewWithExitPortal_HasOutsideViewTrue_AabbMatchesBounds()
+    {
+        // A single convex quad in OutsideView reduces to Planes. HasOutsideView must
+        // be true and OutsideViewNdcAabb must match the polygon's own Min/Max values.
+        var pv = new PortalVisibilityFrame();
+        var poly = Square(-0.3f, 0.2f, 0.25f);
+        pv.OutsideView.Add(poly);
+        // No interior cells needed for this assertion.
+
+        var frame = ClipFrame.NoClip();
+        var asm = ClipFrameAssembler.Assemble(frame, pv);
+
+        Assert.True(asm.HasOutsideView);
+        Assert.Equal(TerrainClipMode.Planes, asm.TerrainMode);
+
+        // The OutsideViewNdcAabb must equal the CellView's accumulated Min/Max.
+        var expected = new System.Numerics.Vector4(
+            pv.OutsideView.MinX, pv.OutsideView.MinY,
+            pv.OutsideView.MaxX, pv.OutsideView.MaxY);
+        Assert.Equal(expected, asm.OutsideViewNdcAabb);
+    }
+
+    [Fact]
+    public void Assemble_OutsideViewMultiPolygon_ScissorMode_HasOutsideViewTrue_AabbValid()
+    {
+        // Two polygons in OutsideView → union (non-convex) → ClipPlaneSet forces
+        // scissor fallback. HasOutsideView must still be true, TerrainMode must be
+        // Scissor, and OutsideViewNdcAabb must equal the union bounds (same values
+        // as TerrainScissorNdcAabb in this mode).
+        var pv = new PortalVisibilityFrame();
+        pv.OutsideView.Add(Square(-0.6f, 0f, 0.15f));
+        pv.OutsideView.Add(Square(0.6f, 0f, 0.15f));
+
+        var frame = ClipFrame.NoClip();
+        var asm = ClipFrameAssembler.Assemble(frame, pv);
+
+        Assert.True(asm.HasOutsideView);
+        Assert.Equal(TerrainClipMode.Scissor, asm.TerrainMode);
+
+        // Union bounds from the CellView (spans both squares).
+        var expectedAabb = new System.Numerics.Vector4(
+            pv.OutsideView.MinX, pv.OutsideView.MinY,
+            pv.OutsideView.MaxX, pv.OutsideView.MaxY);
+        Assert.Equal(expectedAabb, asm.OutsideViewNdcAabb);
+
+        // In Scissor mode OutsideViewNdcAabb and TerrainScissorNdcAabb are the same
+        // value (both are the union CellView bounds).
+        Assert.Equal(asm.TerrainScissorNdcAabb, asm.OutsideViewNdcAabb);
+    }
+
+    [Fact]
+    public void Assemble_EmptyOutsideView_HasOutsideViewFalse_AabbZero()
+    {
+        // An empty OutsideView means no exit portal was in view → TerrainMode.Skip,
+        // HasOutsideView false, OutsideViewNdcAabb degenerate zero.
+        const uint cellA = 0xA9B40100;
+        var pv = new PortalVisibilityFrame();
+        pv.CellViews[cellA] = ViewOf(Square(0f, 0f, 0.3f));
+        pv.OrderedVisibleCells.Add(cellA);
+        // OutsideView left empty (no exit portal).
+
+        var frame = ClipFrame.NoClip();
+        var asm = ClipFrameAssembler.Assemble(frame, pv);
+
+        Assert.False(asm.HasOutsideView);
+        Assert.Equal(TerrainClipMode.Skip, asm.TerrainMode);
+        Assert.Equal(System.Numerics.Vector4.Zero, asm.OutsideViewNdcAabb);
+    }
+
     [Fact]
     public void Reset_ReusesFrame_NoSlotLeakAcrossAssemblies()
     {