feat(meshlet): refactor meshlet pipeline & add benchmark

Refactor meshlet build pipeline for robustness and performance.
Rename DxcShaderCompiler to DXCShaderCompiler. Enhance meshlet
data structures with bounds and LOD info. Add fallback mesh
simplification. Remove obsolete MeshRenderPass. Add
MeshoptBenchmark for meshlet build performance. Update mesh
import utilities for correct handedness. Minor bug fixes and
code cleanups.

src/Test/Ghost.MicroTest/Program.cs

@@ -1,4 +1,4 @@
 using Ghost.MicroTest;
 using Ghost.Test.Core;
 
-TestRunner.Run<UfbxBindingTest>();
+TestRunner.Run<MeshoptBenchmark>();