Update screenshot to show new weather icon

Refreshes images/screenshot.jpg with a current capture that includes
the weather icon in the header, and embeds it in the README (it was
previously unused there - only images/radar.jpg was linked).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -8,6 +8,7 @@ altitude/speed/model/route details and a proximity LED alert.
 ![framework](https://img.shields.io/badge/framework-Arduino%20%2F%20PlatformIO-blue)
 
 ![Eiswolfs Flightradar screenshot](images/radar.jpg)
+![Eiswolfs Flightradar Screenshot](images/screenshot.jpg)
 
 ## Getting Started