A novel takes years. A dissertation takes longer. Here’s how to pick an iPad planner that actually holds the shape of long, slow work — and why most productivity apps were never designed for it. I’m Takeya. I make Planner for iPad. I’m not a novelist and I’m not finishing a PhD, but I’ve spent the better part of a decade on a single product, and I know the specific texture of work that doesn’t pay off for years. That…