On Adam Ganucheau’s first day at Mississippi Today a decade ago, there was no Wi-Fi, and he used an upside-down cardboard box as a desk. These days, things look a little different. What was once a fledgling nonprofit newsroom is now a Pulitzer-winning powerhouse and one of three newsrooms that make up the Deep South Today network, along with two in Louisiana: Verite News in New Orleans and, as of last year, The Current in Lafayette. (The Garriso…