The new menuItem(_:action:key:mods:target:) helper introduced in the
menu reorg defaults `target = self` if no target is passed. AppKit
disables a menu item whose target doesn't respond to its action, so
Quit (action: NSApplication.terminate(_:), which lives on NSApp, not
AppDelegate) ended up greyed out.
Fix: pass `target: NSApp` for the Quit item so AppKit dispatches the
action to NSApplication directly. Hide / Hide Others / Show All were
already passing NSApp explicitly so they were fine.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>