[Bug] Adding NXNavigationBar to UIHostingController.view triggers Apple's warning

[JayDaniel]

Description

When using NXNavigationExtension with UIHostingController (SwiftUI views embedded in UIKit navigation), the console shows this warning:

[SwiftUI] Attempting to add elements to UIHostingController's view is not supported...

This happens because nx_setupNavigationBar adds nx_navigationBar directly to self.view, but for UIHostingController, self.view is a private _UIHostingView which Apple explicitly warns against modifying.

Environment

• iOS 15+ / iOS 17+
• Xcode 15+
• NXNavigationExtension 4.2.6
• Using UIHostingController subclass pushed onto UINavigationController

Steps to Reproduce

1. Create a custom UIHostingController subclass
2. Push it onto a UINavigationController that uses NXNavigationExtension
3. Observe the warning in console

class MyHostingVC<Content: View>: UIHostingController<Content> {
    // ...
}

// Push to navigation stack
let vc = MyHostingVC(rootView: MySwiftUIView())
navigationController?.pushViewController(vc, animated: true)

Root Cause

In UIViewController+NXNavigationExtension.m, line ~292:

- (void)nx_setupNavigationBar {
    // ...
    if (![self.view isKindOfClass:[UIScrollView class]]) {
        [self.view addSubview:self.nx_navigationBar];  // ⚠️ Triggers warning for UIHostingController
    }
}

Since the current project architecture targets iOS 15+ and the main project heavily uses UIKit, embedding SwiftUI pages within a UIKit navigation stack is the best implementation approach for me right now.