Expert focus management guidance for all Apple platforms (tvOS, iOS/iPadOS, watchOS, visionOS). Covers SwiftUI, UIKit, and RealityKit focus APIs including @FocusState, UIFocusEnvironment, UIFocusGuide, focusSection, HoverEffect, Digital Crown routing, and 14 critical anti-patterns that break focus navigation. Built from real-world experience shipping production tvOS apps. 2,100+ lines of reference material across 10 files covering focus styling, focus restoration, layout patterns, and debugging techniques.