Adds ios-scaffold.md reference that explicitly prohibits Package.swift + .executableTarget for iOS apps (produces macOS CLI, not iOS app bundle), requires project.yml + xcodegen generate to create a proper .xcodeproj, and documents SwiftUI API availability tiers (iOS 16 vs 17). Adds iOS anti-patterns 28-29 to universal-anti-patterns.md and wires the reference into gsd-executor.md so executors see the guidance during iOS plan execution. Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>