As summer arrives, Samsung might be getting ready to debut the next generation of Galaxy watches. Mounting evidence for both the Galaxy Watch 9 and Galaxy Watch Ultra 2 continues to emerge through firmware leaks, certification filings and battery reports that paint the clearest picture yet of Samsung's wearable plans.The latest clue comes from a Chinese 3C regulatory filing first spotted by Jeff Springer at SammyGuru, which lists two upcoming smartwatch models believed to be the Galaxy Watch 9 and Galaxy Watch Ultra 2. While the filing itself doesn't reveal much beyond support for 10W charging (the same as last year's…