Nathan Xu’s bootstrapped company has sold more than 1 million AI recording devices that transcribe and summarize the busy days of doctors, lawyers and business people — and he’s just getting started. On a rainy July morning in a plush Amsterdam suburb, Nathan Xu has camped out at an Italian coffee shop for a full slate of meetings. Smiling, he asks if he can record our conversation and clips a slim memory stick-sized device to his shirt. With just a click, the pill-shaped gadget starts recording...