GKLocalPlayer.Authenticate() and GKLocalPlayer.Local.FetchItems() freeze on iOS 26.0 #82

Describe the bug
GKLocalPlayer.Authenticate() and GKLocalPlayer.Local.FetchItems() freeze indefinitely on iOS 26.0. No callbacks, completion, or errors are triggered.

To Reproduce

1. Run the app on a device with iOS 26.0
2. Call GKLocalPlayer.Authenticate()
3. Call GKLocalPlayer.Local.FetchItems()

Expected behavior
Methods complete successfully or return an error.

Desktop (please complete the following information):

• Device: iPhone (any)
• OS: iOS
• Version: 26.0
• Apple.Core: 3.1.8
• Apple.GameKit: 3.1.8

Additional context
Issue does not reproduce on iOS 26.1 - works correctly there.