import SwiftUI /// Environment-Key, der den shared `MediaCache` durch die View-Hierarchie /// reicht. App-Entrypoint setzt den Wert; Views lesen via /// `@Environment(\.mediaCache)`. private struct MediaCacheKey: EnvironmentKey { static let defaultValue: MediaCache? = nil } extension EnvironmentValues { var mediaCache: MediaCache? { get { self[MediaCacheKey.self] } set { self[MediaCacheKey.self] = newValue } } }