feat(apple): Add session replay trouble shooting page with custom window handling (#13753)

## DESCRIBE YOUR PR

During debugging of the SDK we discovered that session replay for iOS
requires on the `window` property of the window scene delegate /
`UIWindowSceneDelegate` to be set. By default this will be set during
the bootstrapping of the app, but it appears that the property can also
be omitted and not configured.

This PR adds documentation to indicate to users how to deal with this.
It's also the start of having a troubleshooting section dedicated to
session replay:


https://sentry-docs-git-philprime-session-replay-scene-delegate.sentry.dev/platforms/apple/guides/ios/session-replay/troubleshooting/

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## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [X] Checked Vercel preview for correctness, including links
- [x] PR was reviewed and approved by any necessary SMEs (subject matter
experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs
team](https://github.com/orgs/getsentry/teams/docs)

## EXTRA RESOURCES

- [Apple
Documentation](https://developer.apple.com/documentation/uikit/uiwindowscenedelegate/window)

---------

Co-authored-by: Jasmin <[email protected]>

Author: philprime

docs/platforms/apple/common/troubleshooting/index.mdx

@@ -226,3 +226,7 @@ To resolve this problem try the following:
 4. Restart Xcode
 5. Reset your package cache if using Swift Package Manager by going to **File > Packages > Reset Package Caches**
 6. Rebuild your project
+
+## Troubleshooting Session Replay
+
+See [Session Replay - Troubleshooting](/platforms/apple/guides/ios/session-replay/troubleshooting) for more information.

docs/platforms/apple/guides/ios/session-replay/troubleshooting.mdx

@@ -0,0 +1,71 @@
+---
+title: Troubleshooting
+sidebar_order: 5503
+notSupported:
+description: "Troubleshoot and resolve common issues with the iOS Session Replay."
+---
+
+## Session Replay is not recording with custom window setup
+
+If you have a custom window setup (e.g., multiple instances of `UIWindow`), you need to ensure that the Sentry SDK is able to find the correct window.
+
+When using window scenes, make sure that the main window is assigned in your `UIWindowSceneDelegate`'s [`window` property](https://developer.apple.com/documentation/uikit/uiwindowscenedelegate/window).
+
+```swift
+final class SceneDelegate: NSObject, UIWindowSceneDelegate {
+
+    var window: UIWindow?
+
+    func scene(
+        _ scene: UIScene,
+        willConnectTo session: UISceneSession,
+        options connectionOptions: UIScene.ConnectionOptions
+    ) {
+        guard let scene = scene as? UIWindowScene else { return }
+
+        // Configure your windows here, e.g.
+        let mainWindow = UIWindow(windowScene: scene)
+        mainWindow.rootViewController = UIViewController()
+        mainWindow.makeKeyAndVisible()
+
+        // Do not forget to assign the window to the SceneDelegate's window property:
+        self.window = mainWindow
+    }
+}
+```
+
+Alternatively, you can also create a custom proxy variable for the window:
+
+```swift
+final class SceneDelegate: NSObject, UIWindowSceneDelegate {
+
+    var mainWindow: UIWindow?
+
+    func scene(
+        _ scene: UIScene,
+        willConnectTo session: UISceneSession,
+        options connectionOptions: UIScene.ConnectionOptions
+    ) {
+        guard let scene = scene as? UIWindowScene else { return }
+
+        // Configure your windows here, e.g.
+        let mainWindow = UIWindow(windowScene: scene)
+        mainWindow.rootViewController = UIViewController()
+        mainWindow.makeKeyAndVisible()
+
+        // Do not forget to assign the window to the SceneDelegate's window property:
+        self.window = mainWindow
+    }
+
+    // This is required to make sure that the Sentry SDK can find the correct window:
+
+    var window: UIWindow? {
+        get {
+            return mainWindow
+        }
+        set {
+            mainWindow = newValue
+        }
+    }
+}
+```