The Biden administration is moving to end a legal battle with California over the state’s authority to regulate motor-vehicle emissions, setting the stage for stricter regulations on the auto industry, according to people briefed on those plans.Administration officials could reveal their initial steps as early as Friday, as President Biden concludes a two-day international summit through video conference to address climate change. It would be the most recent in the series of attempts to unwind Trump administration policies that eased environmental rules. California, the nation’s largest car market, has long set emissions standards that surpass requirements set by the federal government, an irregularity that was allowed under a waiver to the Clean Air Act. As a result, California’s standards ended up being the de facto national standard. That became a starting point of conflict during the Trump years as automakers asked the Trump administration for relief from a deal the Obama administration negotiated with California and the industry to expand fuel -economy standards.