### Summary
When selecting "Quit LightCraft" from the native macOS menu bar, the application occasionally crashes with an `EXC_BAD_INSTRUCTION` (SIGILL) error report during shutdown.
### Root Cause
1. The native menu action triggered `ctx.send_viewport_cmd(egui::ViewportCommand::Close)`.
2. Forcing an explicit viewport close via the command queue while macOS and AppKit are initiating their own termination sequence creates a race condition with `winit`.
3. This conflict during native window, view, and observer teardown leads to an illegal instruction fault.
### Solution
- Replaced the manual `ViewportCommand::Close` trigger on `QUIT` with a clean `std::process::exit(0)`.
- This bypasses the problematic `winit`/AppKit teardown race condition on macOS, allowing the application to shut down instantly and cleanly without generating crash reports.
onemannoplan
5c1dcd4f97