Republican Rep. Tony Gonzales has been forced into a repeat primary runoff with far-right gun activist Brandon Herrera, CBS News projects, weeks after Gonzales was accused of having an affair with an aide who later died by suicide — drawing calls for him to resign.Gonzales and Herrera are locked in a tight contest, with neither candidate expected to clear the 50% threshold required to avoid a runoff on May 26. Gonzales was first elected in 2020, and had branded himself as a moderate. In a primary challenge from Herrera in 2024, Gonzales only prevailed by 400 votes. Gonzales has since pursued a rightward shift and touted his endorsement by President Trump in this race, although Mr. Trump left his name off a list of endorsements on Friday. But Gonzales had been facing calls to resign from members of both parties after texts were revealed last month between him and former aide Regina Santos-Aviles, who died in September after setting herself on fire, according to the Uvalde police.…