Adapter chuyển từ square mesh case sang fan (tối ưu airflow)

This adapter solves a common PC case airflow problem: when a case fan mounts directly against square mesh, the fan's square frame blocks the mesh corners (120mm square vs 112mm circle opening), and the center motor hub blocks even more holes. This adapter spaces the fan away from the mesh while providing a minimal bottom plate that maximizes airflow through the mesh.