Change screenshot source in README.md

[Layellie]

Updated the screenshot in README.md to a new URL.

Summary

Files

Test plan

• dotnet build -c Release — 0 warnings, 0 errors
• Smoke-tested the affected feature manually (UAC accepted, app running)
• Touched a Views/Cards/*.xaml? Resized window, confirmed no layout shift
• Touched a service that owns a PerformanceCounter, Process, or native handle? Verified OnExit still releases it
• Touched a string in Strings.en-US.xaml? Mirrored in Strings.tr-TR.xaml

Release note