DETROIT — Traffic from the U.S. to Canada via the Ambassador Bridge remained blocked Wednesday morning, more than 36 hours after the bridge was completely closed due to a protest by Canadian truck drivers. The Ambassador Bridge reopened to some U.S.-bound traffic early Tuesday morning and fully opened Tuesday afternoon, Windsor police said. The protest against COVID-19 mandates and restrictions in Canada spread Monday across the Canadian border with the U.S., sparking traffic delays. The traffic-blocking convoy was the first sign demonstrations could affect the United States. Many drivers opte…