The Live Activity's End button uses Button(intent:), whose initializer lives in
_AppIntents_SwiftUI — reached via `import AppIntents` (was missing, so the
widget target failed to build). Also replaced the iOS-26-deprecated Text + Text
concatenation in the background countdown with an HStack.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
