Adds Assets.xcassets with a placeholder 1024x1024 AppIcon so Xcode
compiles CFBundleIconName and the required icon sizes into the bundle.
Replaces UILaunchStoryboardName (missing storyboard) with UILaunchScreen
dict, valid for iOS 14+ (min target is iOS 18). Fixes all four App Store
Connect validation errors blocking TestFlight upload.
