For its 25th anniversary edition, Tribeca Festival will host a special conversation with co-founders Robert De Niro and Jane Rosenthal that looks back at the dramatic events that inspired the annual celebration of movies and media. Matt Tyrnauer, the acclaimed director of documentaries such as “Where’s My Roy Cohn?” and “Valentino: The Last Emperor,” will moderate the talk. There will certainly be plenty of fodder for the discussion, as few festivals have unfolded against such a harrowing backdrop. Tribeca, which initially was rooted in downtown New York, was launched in just 120 days to help lower Manhattan as it recovered from the 9/11 attacks. De Niro, the Oscar-winning star of “Raging Bull” and “Goodfellas,” and Rosenthal, the producer of “Meet the Parents,” tapped their extensive networks to program a roster of A-list talent and premieres. In an interview with Variety last year, Rosenthal reflected on that chaotic and consequential first festival. “Nobody was coming downtown after 9/11,” she said.…