fix(onboarding): open Settings via SwiftUI openSettings action

macos/Codescribe/Screens/Onboarding/OnboardingSteps.swift

@@ -241,6 +241,12 @@ struct HotkeyModeStepView: View {
 
 struct AgenticReadinessStepView: View {
     @ObservedObject var model: OnboardingViewModel
+    // macOS 14+ action to open the app's Settings scene. This accessory /
+    // LSUIElement app has no responder for the private `showSettingsWindow:`
+    // selector, so the SwiftUI environment action is the only reliable open path
+    // (matching TrayMenuView / AgentChatView). The Settings scene activates the
+    // app and orders its window front, above the wizard.
+    @Environment(\.openSettings) private var openSettings
 
     var body: some View {
         VStack(alignment: .leading, spacing: 16) {
@@ -298,7 +304,8 @@ struct AgenticReadinessStepView: View {
                 .fixedSize(horizontal: false, vertical: true)
             HStack(spacing: 10) {
                 OnboardingButton(title: "Set up MCP servers", kind: .primary) {
-                    model.openMcpSettings()
+                    model.prepareMcpSettingsDeepLink()
+                    openSettings()
                 }
                 OnboardingButton(title: "Skip for now", kind: .secondary) {
                     model.dismissMcpSetupPrompt()

macos/Codescribe/Screens/Onboarding/OnboardingViewModel.swift

@@ -1,4 +1,3 @@
-import AppKit
 import SwiftUI
 
 // State machine for the first-run wizard: current step index (persisted on every
@@ -217,15 +216,15 @@ final class OnboardingViewModel: ObservableObject {
         mcpStatus = agentStatus.mcpStatus()
     }
 
-    /// Route the user to the live MCP management surface (Settings › Engine) via a
-    /// one-shot deep-link, then open the standard Settings window. The wizard stays
-    /// open behind it, so the user can wire a server and return to continue.
-    func openMcpSettings() {
+    /// Arm the one-shot deep-link so the Settings window lands on the MCP surface
+    /// (Settings › Engine). The view owns the actual open via SwiftUI's
+    /// `@Environment(\.openSettings)` — the only reliable path in this accessory /
+    /// LSUIElement app, where the private `showSettingsWindow:` selector has no
+    /// responder (matching TrayMenuView / AgentChatView). Call this immediately
+    /// before `openSettings()`; the wizard stays open behind Settings so the user
+    /// can wire a server and return to continue.
+    func prepareMcpSettingsDeepLink() {
         SettingsDeepLink.pendingSection = .engine
-        if !NSApp.sendAction(Selector(("showSettingsWindow:")), to: nil, from: nil) {
-            // Older selector name kept as a defensive fallback.
-            _ = NSApp.sendAction(Selector(("showPreferencesWindow:")), to: nil, from: nil)
-        }
     }
 
     /// Dismiss the MCP setup prompt for this session so onboarding proceeds without