Shoppers and diners 12 and older in the nation’s capital now have to show proof of COVID-19 vaccination under new rules that took effect on Saturday. Washington Mayor Muriel Bowser’s executive orders, announced last month, force people entering a range of indoor venues to prove they’ve gotten a COVID-19 vaccine by using the paper card people get when receiving a jab, a record of the card, or a verification application. The mandate applies to people entering restaurants, nightclubs, and coffee shops; movie theaters, bowling alleys, and venues hosting concerts; gyms, fitness studios, and any facilities used for group fitness classes; and venues for indoor events and meetings. Bowser, a Democrat, said the mandate was a way to ensure hospitals in the city don’t get overwhelmed amid a spike in COVID-19 cases. Republicans urged Bowser to rescind the mandate before it took effect, arguing it would disproportionately harm businesses in the …