feat: --login-item launch argument for headless nodes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

App/Sources/Coordinator.swift

@@ -40,12 +40,20 @@ final class Coordinator {
 
         outputs.applyLaunchRoutes()
         audio.applyLaunchRoutes()
+        applyLoginItemArgument()
 
         statusTimer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { [weak self] _ in
             MainActor.assumeIsolated { self?.sendStatus() }
         }
     }
 
+    /// `--login-item on|off`: set up a headless node over SSH, where the settings window is hidden behind outputs.
+    private func applyLoginItemArgument(_ arguments: [String] = ProcessInfo.processInfo.arguments) {
+        guard let index = arguments.firstIndex(of: "--login-item"), index + 1 < arguments.count else { return }
+        settings.launchAtLogin = arguments[index + 1] == "on"
+        Log.ndi.info("Launch at login: \(self.settings.launchAtLogin ? "on" : "off", privacy: .public)")
+    }
+
     /// (Re)starts the Bonjour side that fits the role; call after role or interface changes.
     func startRemote() async {
         nodeServer?.stop()