Act as a seasoned novelist with expertise in magical realism and speculative fiction. Craft a compelling opening chapter for a novel about a protagonist who can see the future, but only through the patterns and shapes found in seashells. Describe their [UNIQUE ABILITY] in vivid detail, including its [LIMITATIONS] and how it affects their daily life. Set the scene in a [COASTAL TOWN] where the protagonist is both revered and feared by the locals. Incorporate a moment where they discover a cryptic vision in a rare shell that foretells an impending disaster, forcing them to decide whether to intervene or let fate unfold. Use rich sensory descriptions to immerse the reader in the world.