Add screenshot showing QR Code scanner in settings

- Added screenshots directory with settings page image
- Shows the new "Scan QR Code" green button prominently
- Updated README.md to use the new screenshot
- Added caption to explain what each screenshot shows

This gives users a clear visual of the new QR scanner feature
before downloading the app.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: supg

README.md

@@ -85,7 +85,9 @@ If you enjoy the original app, support the developer:
 If you use Kimai as self hosted, you have to configure SSL (HTTPS). __App work only with HTTPS__.
 
 # Screenshots
-<img src="https://github.com/user-attachments/assets/af797736-c806-4723-b5c1-b601cfa15e93" width="250"/>
-<img src="https://github.com/user-attachments/assets/7a8c6de7-9b13-4958-a7de-04c647553973" width="250"/>
+
+<img src="https://github.com/user-attachments/assets/af797736-c806-4723-b5c1-b601cfa15e93" width="250"/> <img src="screenshots/settings-qr-scanner.jpeg" width="250"/>
+
+*Left: Main time tracking screen | Right: Settings with new "Scan QR Code" button*