Update README with professional support information

Added a section for professional support and consulting services.

Author: DmitryTsepelev

README.md

@@ -9,7 +9,10 @@ class PostType < BaseObject
 end
 ```
 
-You can support my open–source work [here](https://boosty.to/dmitry_tsepelev).
+## Professional Support
+
+Need help with your GraphQL API architecture, schema design, or performance?
+I'm available for consulting — [get in touch](https://dmitrytsepelev.dev/consulting).
 
 ## Getting started