WELLINGTON, Ohio — Former President Trump made his triumphant return to the campaign trail and social media on Saturday night, receiving a rock star’s welcome from thousands who turned out in pro-Trump apparel to show their support for him, his claims of a stolen election and a possible comeback in 2024. At the Lorain County fairgrounds west of Cleveland, Mr. Trump quickly launched into an attack of the Biden administration as “a complete and total catastrophe.” He said Republicans must end Democrats’ control of the White House and Congress over the next two election cycles and “take back America.”