fix(ios): defer SwiftUI host setup until reactViewController is ready

ios/PagerViewProvider.swift

@@ -91,6 +91,13 @@ import UIKit
     }
   }
 
+  override public func layoutSubviews() {
+    super.layoutSubviews()
+    if window != nil {
+      setupView()
+    }
+  }
+
   @objc public func goTo(index: Int, animated: Bool) {
     if animated {
       withAnimation {
@@ -106,19 +113,32 @@ import UIKit
       return
     }
 
-    self.hostingController = UIHostingController(
+    // Only create the hosting controller once it can actually be attached to the
+    // React view-controller hierarchy. `reactViewController()` can be nil on the
+    // first `didMoveToWindow` pass (e.g. when the pager is mounted inside a screen
+    // that is still being attached). Previously `self.hostingController` was
+    // assigned before this check, so when `reactViewController()` was nil the
+    // SwiftUI host was never added/pinned (its view frame stayed `.zero`, leaving
+    // the page blank) while the early-return above prevented any later retry.
+    // Deferring keeps `hostingController` nil so a subsequent window/layout pass
+    // can attach it once the view controller is available.
+    guard let parentViewController = reactViewController() else {
+      return
+    }
+
+    let hostingController = UIHostingController(
       rootView: PagerView(props: props, delegate: delegate),
       ignoreSafeArea: true
     )
-    if let hostingController, let parentViewController = reactViewController() {
-      parentViewController.addChild(hostingController)
-      hostingController.view.backgroundColor = .clear
-      addSubview(hostingController.view)
+    self.hostingController = hostingController
 
-      hostingController.view.translatesAutoresizingMaskIntoConstraints = false
-      hostingController.view.pinEdges(to: self)
+    parentViewController.addChild(hostingController)
+    hostingController.view.backgroundColor = .clear
+    addSubview(hostingController.view)
 
-      hostingController.didMove(toParent: parentViewController)
-    }
+    hostingController.view.translatesAutoresizingMaskIntoConstraints = false
+    hostingController.view.pinEdges(to: self)
+
+    hostingController.didMove(toParent: parentViewController)
   }
 }