Fix thread safety and improve API access pattern

Co-authored-by: troZee <12766071+troZee@users.noreply.github.com>

Author: Copilot

ios/PagerGestureDelegate.swift

@@ -12,65 +12,72 @@ class PagerGestureDelegate: NSObject, UIGestureRecognizerDelegate {
   private var gestureObserver: NSKeyValueObservation?
 
   func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
-    // iOS 26+ full-screen back gesture (interactiveContentPopGestureRecognizer)
+    // Get the navigation controller
+    guard let collectionView = collectionView,
+          let viewController = collectionView.reactViewController(),
+          let navigationController = viewController.navigationController else {
+      return false
+    }
+    
+    // Check if this is the pager's pan gesture
+    guard gestureRecognizer == collectionView.panGestureRecognizer else {
+      return false
+    }
+    
+    // Determine which navigation gesture recognizer to check
+    var navGestureRecognizer: UIGestureRecognizer? = navigationController.interactivePopGestureRecognizer
+    
+    // iOS 26+ introduces interactiveContentPopGestureRecognizer for full-screen back gestures
     if #available(iOS 26, *) {
-      // Get the navigation controller's interactive content pop gesture recognizer
-      guard let collectionView = collectionView,
-            let viewController = collectionView.reactViewController(),
-            let navigationController = viewController.navigationController else {
-        return false
-      }
-      
-      // iOS 26 introduces interactiveContentPopGestureRecognizer for full-screen back gestures
-      // We need to check if this property exists and use it, otherwise fall back to standard behavior
-      let interactiveGesture: UIGestureRecognizer?
-      if let contentPopGesture = navigationController.value(forKey: "interactiveContentPopGestureRecognizer") as? UIGestureRecognizer {
-        interactiveGesture = contentPopGesture
-      } else {
-        // Fallback to standard interactivePopGestureRecognizer
-        interactiveGesture = navigationController.interactivePopGestureRecognizer
+      // Try to access the new property safely using selector
+      let selector = NSSelectorFromString("interactiveContentPopGestureRecognizer")
+      if navigationController.responds(to: selector),
+         let contentPopGesture = navigationController.perform(selector)?.takeUnretainedValue() as? UIGestureRecognizer {
+        navGestureRecognizer = contentPopGesture
       }
+    }
+    
+    // Check if the other gesture is the navigation back gesture
+    guard let navGesture = navGestureRecognizer,
+          otherGestureRecognizer == navGesture else {
+      return false
+    }
+    
+    // Get velocity to determine swipe direction
+    guard let panGestureRecognizer = gestureRecognizer as? UIPanGestureRecognizer else {
+      return false
+    }
+    
+    let velocity = panGestureRecognizer.velocity(in: collectionView)
+    let isLTR = layoutDirection == .ltr
+    let isBackGesture = (isLTR && velocity.x > 0) || (!isLTR && velocity.x < 0)
+    
+    // If on first page and performing back gesture, disable pager scroll to allow navigation
+    if currentPage == 0 && isBackGesture {
+      collectionView.panGestureRecognizer.isEnabled = false
 
-      // Check if this is the pager's pan gesture and the other is the navigation back gesture
-      if gestureRecognizer == collectionView.panGestureRecognizer,
-         otherGestureRecognizer == interactiveGesture {
+      // Observe gesture state to re-enable when gesture ends
+      gestureObserver?.invalidate()
+      gestureObserver = otherGestureRecognizer.observe(\.state, options: [.new]) { [weak self, weak collectionView] _, change in
+        guard let self = self, 
+              let collectionView = collectionView,
+              let newState = change.newValue else { return }
 
-        // Get velocity to determine swipe direction
-        guard let panGestureRecognizer = gestureRecognizer as? UIPanGestureRecognizer else {
-          return false
-        }
-        
-        let velocity = panGestureRecognizer.velocity(in: collectionView)
-        let isLTR = layoutDirection == .ltr
-        let isBackGesture = (isLTR && velocity.x > 0) || (!isLTR && velocity.x < 0)
-        
-        // If on first page and performing back gesture, disable pager scroll to allow navigation
-        if currentPage == 0 && isBackGesture {
-          collectionView.panGestureRecognizer.isEnabled = false
-          
-          // Observe gesture state to re-enable when gesture ends
-          gestureObserver?.invalidate()
-          gestureObserver = otherGestureRecognizer.observe(\.state, options: [.new]) { [weak self, weak collectionView] _, change in
-            guard let self = self, 
-                  let collectionView = collectionView,
-                  let newState = change.newValue else { return }
-            
-            // Re-enable pager scroll when navigation gesture ends
-            if newState == .ended || newState == .cancelled || newState == .failed {
-              collectionView.panGestureRecognizer.isEnabled = self.scrollEnabled
-              self.gestureObserver?.invalidate()
-              self.gestureObserver = nil
-            }
+        // Re-enable pager scroll when navigation gesture ends
+        if newState == .ended || newState == .cancelled || newState == .failed {
+          // Ensure UIKit updates happen on main queue
+          DispatchQueue.main.async {
+            collectionView.panGestureRecognizer.isEnabled = self.scrollEnabled
           }
-        } else {
-          collectionView.panGestureRecognizer.isEnabled = scrollEnabled
+          self.gestureObserver?.invalidate()
+          self.gestureObserver = nil
         }
-        
-        return true
       }
+    } else {
+      collectionView.panGestureRecognizer.isEnabled = scrollEnabled
     }
 
-    return false
+    return true
   }
 
   deinit {