YAOUNDÉ, Cameroon — As ministerial talks at the World Trade Organization stretched into overtime on Sunday evening, the delegates who had not yet caught their flights home were bracing for a decision on how a work plan to overhaul the struggling institution can move forward. At the center of the impasse was the fate of the e-commerce moratorium, a long-standing ban on digital tariffs set to expire Tuesday. Negotiations were continuing behind closed doors on what was meant to be the final day of