refactor(runtime): acknowledge exact world host projections

tests/AcDream.App.Tests/Streaming/WorldGenerationQuiescenceTests.cs

@@ -144,6 +144,39 @@ public sealed class WorldGenerationQuiescenceTests
         Assert.Equal(inventoryGuid, selection.SelectedObjectId);
     }
 
+    [Fact]
+    public void ReentrantBeginDuringAudioResume_ReconcilesToNewestEdge()
+    {
+        var transit = new RuntimeWorldTransitState();
+        var world = new GpuWorldState(
+            availability: new WorldGenerationAvailabilityState(transit));
+        var audio = new ReentrantAudioQuiescence();
+        var quiescence = new WorldGenerationQuiescence(
+            new SelectionState(),
+            world,
+            _ => null,
+            audio);
+        var edge = new WorldGenerationQuiescenceEdge(
+            ShouldApply: true,
+            ClearWorldSelection: false);
+        quiescence.CommitBegin(edge);
+        audio.OnResume = () =>
+        {
+            audio.OnResume = null;
+            quiescence.CommitBegin(edge);
+        };
+
+        quiescence.ObserveReleased();
+
+        Assert.Equal(2, audio.SuspendCalls);
+        Assert.Equal(1, audio.ResumeCalls);
+
+        quiescence.ObserveReleased();
+
+        Assert.Equal(2, audio.SuspendCalls);
+        Assert.Equal(2, audio.ResumeCalls);
+    }
+
     private static RuntimeDestinationReadiness Ready(
         long generation,
         uint destinationCell) =>
@@ -178,4 +211,19 @@ public sealed class WorldGenerationQuiescenceTests
         public void SuspendWorldAudio() => SuspendCalls++;
         public void ResumeWorldAudio() => ResumeCalls++;
     }
+
+    private sealed class ReentrantAudioQuiescence : IWorldAudioQuiescence
+    {
+        public int SuspendCalls { get; private set; }
+        public int ResumeCalls { get; private set; }
+        public Action? OnResume { get; set; }
+
+        public void SuspendWorldAudio() => SuspendCalls++;
+
+        public void ResumeWorldAudio()
+        {
+            ResumeCalls++;
+            OnResume?.Invoke();
+        }
+    }
 }