Add FPS counter and performance monitor to UI #2
Description
Is your feature request related to a problem?
Yes, there's no way to see FPS or performance info while using the app.
Describe the solution you'd like
Add a small window in the UI that shows:
- FPS (frames per second)
- Frame time in milliseconds
- Memory usage
- Number of planets/asteroids being rendered
Describe alternatives you've considered
Could use external tools, but built-in would be better.
Additional context
This would help users understand performance and help developers optimize the code.