Explore a warm, detailed news-style feature about Megadeth’s farewell tour prompted by Dave Mustaine’s battle with Dupuytren’s contracture. Describe the tour’s kickoff, the emotional impact on fans, and the implications for future metal tours, drawing on the provided set list, tour timeline, and Mustaine’s statements about continuing to tour for years. Craft it as a human-interest news report that centers on the performers, fans, and the broader live-metal touring landscape.