SACRAMENTO — Gov. Gavin Newsom’s administration unexpectedly yanked its support from a sweeping proposal that would have protected millions of California’s indoor workers from dangerous heat, saying it can’t endorse it without knowing the projected costs to the state. But the board that oversees worker safety immediately defied the administration Thursday by unanimously approving new standards intended to protect people who work in poorly ventilated warehouses, steamy restaurant kitchens, and other indoor job sites. The showdown represents a setback to the state’s climate and labor policy goal…