uikit-app-modernizationlisted

# UIKit App Modernization Skill ## Purpose Modernize UIKit apps to behave correctly on modern iOS by: - Eliminating references to legacy shared-state APIs - Migrating from application lifecycle to scene lifecycle - Supporting dynamic scene sizing and multi-window environments ## Scope This skill performs **specific, targeted modernizations** in both **Swift and Objective-C** codebases: - Replace legacy shared-state APIs with context-appropriate modern APIs - Migrate to scene-based lifecycle - Update apps to support a resizable user interface by removing usage of: - main screen (`UIScreen.mainScreen`, `UIScreen.main`) - interface orientation (`interfaceOrientation`) - assumptions of symmetric safe areas (`safeAreaLayoutGuide`, `safeAreaInsets`) ## Core Principles 1. **Closest to consumer** — Prefer information nearest the point of use (e.g., view's trait collection over window's). 2. **Always apply a replacement when the target API is present.** A TODO alone is a failure. **An empty diff for a file containing the target API is also a failure.** If the file contains the target deprecated API and a concrete replacement is feasible under any pattern in the active task's reference file, apply it. Only skip when the target API appears exclusively inside dead code (`#if 0`/`#endif`). When uncertain between two valid replacements, pick the one that best fits the user's request rather than producing an empty diff. **Never silently skip a file**: if you are unwilling to app