feat(render): unify physical residency accounting

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

@@ -6,6 +6,40 @@ namespace AcDream.App.Tests.Rendering;
 
 public sealed class CompositeTextureArrayCachePolicyTests
 {
+    [Fact]
+    public void ResidencySnapshotSeparatesResidentRequestedAndRetiringStorage()
+    {
+        var backend = new FakeBackend(maximumLayers: 1);
+        var retirements = new DeferredRetirementQueue();
+        using var cache = CreateCache(
+            backend,
+            retirements,
+            unownedBudgetBytes: 0,
+            physicalBudgetBytes: 0);
+        cache.BeginFrame();
+        Assert.True(cache.TryAddAndAcquire(
+            1,
+            Key(1),
+            Texture(4, 4),
+            out _));
+
+        var resident = cache.CaptureResidency();
+        Assert.Equal(64, resident.Charges.GpuResidentBytes);
+        Assert.Equal(0, resident.Charges.RetiringBytes);
+        Assert.Equal(64, resident.CapacityBytes);
+        Assert.Equal(64, resident.UsedBytes);
+
+        cache.ReleaseOwner(1);
+        cache.Tick();
+        retirements.DrainAll();
+        cache.Tick();
+
+        var retired = cache.CaptureResidency();
+        Assert.Equal(0, retired.Charges.GpuResidentBytes);
+        Assert.Equal(0, retired.Charges.RetiringBytes);
+        Assert.Equal(0, retired.CapacityBytes);
+    }
+
     [Theory]
     [InlineData(16, 16, 64)]
     [InlineData(128, 128, 64)]