Minimizing window closes the app on Windows

**Describe the bug**
On Windows, clicking the **minimize button** (top-right corner of the window) causes A/B Street to **immediately close** instead of minimizing to the taskbar.

**To Reproduce**
Steps to reproduce the behavior:

1. Launch `target/release/game.exe`
2. Click the "minimize" button on the top-right corner
3. The application closes instead of minimizing

**Expected behavior**
The app should stay open in the background or minimize to the taskbar like standard Windows applications.