Melinda Haughey (left) and Chelsey Roney, founders of Proxi, created a tool for making interactive maps. A team whose venture-backed startup was inspired by a map they created for trick-or-treaters. A tech-company product manager who decided to quit his job during an eight-state road trip. A website developer who saw an opportunity to help small businesses reach customers online. These are among the entrepreneurs who created new businesses during the Covid-19 pandemic, a time when the highest number of Americans since at least the mid-2000s took the first steps to launch a new venture.