fix(rendering): match empty packed submissions

The production dispatcher forces transparent deferral off when no top-level VAO was resolved, even if the frame alpha queue is active. Carry the same per-draw VAO sentinel into the compare-only packed classifier so its empty-submission state is exact rather than sampling only the later queue state.

src/AcDream.App/Rendering/Wb/WbDrawDispatcher.PackedOracle.cs

@@ -85,6 +85,7 @@ public sealed unsafe partial class WbDrawDispatcher
              rangeIndex++)
         {
             _nextPackedInstanceSubmissionOrder = 0;
+            uint anyVao = 0;
             foreach (InstanceGroup group in _packedGroups.Values)
                 group.ClearPerInstanceData();
 
@@ -134,11 +135,13 @@ public sealed unsafe partial class WbDrawDispatcher
                     in candidate,
                     meshParts.Slice(
                         source.MeshPartOffset,
-                        source.MeshPartCount));
+                        source.MeshPartCount),
+                    ref anyVao);
             }
 
-            bool deferTransparent =
+            bool deferTransparent = ShouldDeferPackedTransparent(
-                _alphaQueue?.IsCollecting == true;
+                anyVao,
+                _alphaQueue?.IsCollecting == true);
             InstanceLayoutCounts counts = PartitionInstanceGroups(
                 _packedGroups.Values,
                 deferTransparent,
@@ -165,7 +168,8 @@ public sealed unsafe partial class WbDrawDispatcher
 
     private void ClassifyPackedEntity(
         in RenderInstanceCandidate entity,
-        ReadOnlySpan<RenderFrameMeshPart> meshParts)
+        ReadOnlySpan<RenderFrameMeshPart> meshParts,
+        ref uint anyVao)
     {
         (uint slot, bool culled) = ResolveSlotForFrame(
             _clipRoutingActive,
@@ -216,6 +220,8 @@ public sealed unsafe partial class WbDrawDispatcher
                 _meshAdapter.TryGetRenderData(meshRef.GfxObjId);
             if (renderData is null)
                 continue;
+            if (anyVao == 0)
+                anyVao = renderData.VAO;
 
             if (renderData.IsSetup
                 && renderData.SetupParts.Count > 0)
@@ -291,6 +297,16 @@ public sealed unsafe partial class WbDrawDispatcher
         }
     }
 
+    /// <summary>
+    /// Mirrors the production dispatcher's no-VAO early return. That return
+    /// records an empty submission with transparent deferral disabled even
+    /// when the frame alpha queue is collecting.
+    /// </summary>
+    internal static bool ShouldDeferPackedTransparent(
+        uint anyVao,
+        bool alphaQueueCollecting) =>
+        anyVao != 0 && alphaQueueCollecting;
+
     private float PackedPartOpacity(
         uint localEntityId,
         uint setupPartIndex)

tests/AcDream.App.Tests/Rendering/Wb/PackedDispatcherOracleTests.cs

@@ -0,0 +1,23 @@
+using AcDream.App.Rendering.Wb;
+
+namespace AcDream.App.Tests.Rendering.Wb;
+
+public sealed class PackedDispatcherOracleTests
+{
+    [Theory]
+    [InlineData(0u, false, false)]
+    [InlineData(0u, true, false)]
+    [InlineData(7u, false, false)]
+    [InlineData(7u, true, true)]
+    public void TransparentDeferral_MatchesProductionNoVaoEarlyReturn(
+        uint anyVao,
+        bool alphaQueueCollecting,
+        bool expected)
+    {
+        Assert.Equal(
+            expected,
+            WbDrawDispatcher.ShouldDeferPackedTransparent(
+                anyVao,
+                alphaQueueCollecting));
+    }
+}