In large swaths of the country, the holiday weekend that traditionally marks the unofficial start of the summer also kicked off a post-vaccine return to normalcy. Last call in Kentucky bars stretched into the wee hours of Saturday after the governor lifted a curfew. Gamblers on a Boston casino floor counted down to 12:01 a.m. Saturday when Massachusetts restrictions ended, chanting “It’s all over” as they ripped off their masks, sipped Champagne and watched workers remove plexiglass slot machine dividers. Jersey Shore revelers rushed to reopened dance floors... Nightclubs in Boston scrambled to staff their bars and revive their sound systems in time for the Memorial Day weekend reopening — well before the August goal originally set by Gov. Charlie Baker (R). Royale, the largest club in Boston’s theater district, hit its 1,200-person capacity before midnight and had to turn away some customers who had waited in line for more than an hour. “It felt like the end of Prohibition, that everyone wants to come out and celebrate,” said Jamison LaGuardia, vice president for sales, operations and events at Royale Entertainment Group.