메뉴 막대 유틸리티, 그리고 아무도 못 보는 아이콘

import AppKit

@MainActor
final class StatusBarController: NSObject {
    // Hold the item: you need it to change the icon, to remove it, and to ask where it landed.
    private let item: NSStatusItem
    private let menu = NSMenu()
    private let settingsWindow: NSWindow

    init(settingsWindow: NSWindow) {
        self.settingsWindow = settingsWindow
        item = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
        super.init()
        item.button?.image = NSImage(systemSymbolName: "sparkles", accessibilityDescription: "Spark")
        item.button?.image?.isTemplate = true   // follows light, dark and tinted menu bars

        let settings = NSMenuItem(title: "Settings…", action: #selector(showSettings), keyEquivalent: ",")
        settings.target = self
        menu.addItem(settings)
        menu.addItem(.separator())
        menu.addItem(NSMenuItem(title: "Quit Spark", action: #selector(NSApplication.terminate(_:)), keyEquivalent: "q"))
        item.menu = menu

        // The item's window belongs to Control Center, so a probe filtering on this pid finds nothing. Report it here.
        Task { [weak self] in
            try? await Task.sleep(for: .seconds(2))
            guard let self else { return }
            let frame = self.item.button?.window?.frame
            print("spark: status item isVisible=\(self.item.isVisible) frame=\(frame.map { "\($0)" } ?? "none")")
        }
    }

    @objc private func showSettings() {
        settingsWindow.makeKeyAndOrderFront(nil)
        NSApp.activate()   // an accessory app is not frontmost until it asks
    }
}

let app = NSApplication.shared
app.setActivationPolicy(.accessory)   // the code twin of LSUIElement = true in Info.plist
let window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: 420, height: 280),
                      styleMask: [.titled, .closable], backing: .buffered, defer: false)
window.isReleasedWhenClosed = false
let statusBar = StatusBarController(settingsWindow: window)
app.run()