feat: add face-culled chunk mesher behind IChunkMesher

World/IChunkMesher.cs

@@ -0,0 +1,7 @@
+namespace VoxelEngine.World;
+
+public interface IChunkMesher
+{
+    // Returns interleaved vertices: [pos.x, pos.y, pos.z, u, v, shade] per vertex.
+    float[] Build(Chunk chunk, BlockRegistry registry);
+}