Fix intermittent crash on launch-at-login — When launchd started FanBar as a login item before the WindowServer connection was ready, creating an NSStatusItem too early inside SwiftUI’s App.init() hit an AppKit/SkyLight connection assertion and aborted, showing up as “crashes on launch, icon never appears”; status-item creation now waits for applicationDidFinishLaunching, which AppKit only calls once its own startup sequence has finished