[Bug] macOS UI freezes after switching apps or Spaces #806

What happens

After I switch away from Zeron and return, the window sometimes stops repainting and ignores mouse clicks. In fullscreen, this happens after switching to another macOS Space. It also happens in windowed mode after switching to another app.

The agents keep running. Ctrl+Tab still switches sessions while the UI looks frozen, and the selected session appears after the UI recovers. Leaving fullscreen or switching between windows three to five times usually restores interaction. This has happened since I started using Zeron.

Steps to reproduce

1. Open Zeron.
2. Switch to another Space and return while fullscreen, or switch to another app and return while windowed.
3. Observe that the UI stops repainting and ignores clicks.

Expected

Zeron repaints and accepts mouse input after returning.

Environment

• Zeron 0.2.103
• macOS 26.6.2

Notes

Zeron 0.2.103 includes the related ZUI #3 frame-source recovery fix through Zeron #265, but the freeze still happens for me. I have not confirmed whether it has the same cause. A short process sample taken around the occurrence showed the main thread waiting in AppKit and did not identify the rendering failure. I can provide diagnostics if useful; I have not attached raw logs.