iOS onboarding: prevent pairing flicker during auto-resume (#20310)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: 691808b747
Co-authored-by: mbelinky <132747814+mbelinky@users.noreply.github.com>
Co-authored-by: mbelinky <132747814+mbelinky@users.noreply.github.com>
Reviewed-by: @mbelinky

apps/ios/Sources/Onboarding/OnboardingWizardView.swift

@@ -1,4 +1,5 @@
 import CoreImage
+import Combine
 import OpenClawKit
 import PhotosUI
 import SwiftUI
@@ -68,6 +69,7 @@ struct OnboardingWizardView: View {
     @State private var scannerError: String?
     @State private var selectedPhoto: PhotosPickerItem?
     @State private var lastPairingAutoResumeAttemptAt: Date?
+    private static let pairingAutoResumeTicker = Timer.publish(every: 2.0, on: .main, in: .common).autoconnect()
 
     let allowSkip: Bool
     let onClose: () -> Void
@@ -271,6 +273,7 @@ struct OnboardingWizardView: View {
         }
         .onChange(of: self.appModel.gatewayServerName) { _, newValue in
             guard newValue != nil else { return }
+            self.showQRScanner = false
             self.statusLine = "Connected."
             if !self.didMarkCompleted, let selectedMode {
                 OnboardingStateStore.markCompleted(mode: selectedMode)
@@ -282,6 +285,9 @@ struct OnboardingWizardView: View {
             guard newValue == .active else { return }
             self.attemptAutomaticPairingResumeIfNeeded()
         }
+        .onReceive(Self.pairingAutoResumeTicker) { _ in
+            self.attemptAutomaticPairingResumeIfNeeded()
+        }
     }
 
     @ViewBuilder
@@ -685,7 +691,16 @@ struct OnboardingWizardView: View {
         Task { await self.retryLastAttempt() }
     }
 
+    private func resumeAfterPairingApprovalInBackground() {
+        // Keep the pairing issue sticky to avoid visual flicker while we probe for approval.
+        self.appModel.gatewayAutoReconnectEnabled = true
+        self.appModel.gatewayPairingPaused = false
+        self.appModel.gatewayPairingRequestId = nil
+        Task { await self.retryLastAttempt(silent: true) }
+    }
+
     private func attemptAutomaticPairingResumeIfNeeded() {
+        guard self.scenePhase == .active else { return }
         guard self.step == .auth else { return }
         guard self.issue.needsPairing else { return }
         guard self.connectingGatewayID == nil else { return }
@@ -695,7 +710,7 @@ struct OnboardingWizardView: View {
             return
         }
         self.lastPairingAutoResumeAttemptAt = now
-        self.resumeAfterPairingApproval()
+        self.resumeAfterPairingApprovalInBackground()
     }
 
     private func detectQRCode(from data: Data) -> String? {
@@ -837,11 +852,13 @@ struct OnboardingWizardView: View {
         await self.gatewayController.connectManual(host: host, port: self.manualPort, useTLS: self.manualTLS)
     }
 
-    private func retryLastAttempt() async {
-        self.connectingGatewayID = "retry"
+    private func retryLastAttempt(silent: Bool = false) async {
+        self.connectingGatewayID = silent ? "retry-auto" : "retry"
         // Keep current auth/pairing issue sticky while retrying to avoid Step 3 UI flip-flop.
-        self.connectMessage = "Retrying…"
-        self.statusLine = "Retrying last connection…"
+        if !silent {
+            self.connectMessage = "Retrying…"
+            self.statusLine = "Retrying last connection…"
+        }
         defer { self.connectingGatewayID = nil }
         await self.gatewayController.connectLastKnown()
     }