SHANGHAI — Chinese tech giant Huawei said Monday that it had achieved a breakthrough that would allow it to make cutting-edge chips within five years, touting the news as a significant milestone in Beijing’s effort to circumvent U.S. technology restrictions . With the United States and China vying for global dominance in artificial intelligence , U.S. sanctions that began in 2019 have largely cut Huawei off from global makers of semiconductor chips, the tiny brains that power everything from