The rumor mill is churning again, and this time it's about something we've all been quietly hoping for: Touch ID on our wrists. Fresh code discoveries hint that Apple's been quietly working on biometric authentication for the Apple Watch, along with a handful of other features that could transform how we interact with our wearables. Sound familiar? It should—Apple's been dancing around this idea for years, but now the pieces are falling into place at exactly the right moment. What you need ...