perf(render): consume prepared mesh package at runtime

src/AcDream.App/Rendering/GameWindowLifetime.cs

@@ -120,6 +120,7 @@ internal sealed record RenderShutdownRoots(
 
 internal sealed record PlatformShutdownRoots(
     IDatReaderWriter? Dats,
+    IPreparedAssetSource? PreparedAssets,
     IInputContext? Input,
     GL? Gl);
 
@@ -460,6 +461,7 @@ internal static class GameWindowShutdownManifest
             ]),
             new ResourceShutdownStage("content mappings",
             [
+                Hard("prepared asset source", () => platform.PreparedAssets?.Dispose()),
                 Hard("DAT collection", () => platform.Dats?.Dispose()),
             ]),
             new ResourceShutdownStage("input context",