chore: remove Scarf tracking pixel from README

GitHub's camo proxy strips viewer identity, making >50% of pixel
views unattributable. The pixel on GitHub README provides minimal
actionable data.

Author: saurabhjain1592

README.md

@@ -600,5 +600,3 @@ If you are evaluating AxonFlow in a company setting and cannot open a public iss
 [Anonymous evaluation feedback form](https://getaxonflow.com/feedback)
 
 No email required. Optional contact if you want a response.
-
-<img referrerpolicy="no-referrer-when-downgrade" src="https://static.scarf.sh/a.png?x-pxid=ebd08248-7b5b-408f-8f54-cc062bd41c72" />