Update README: standardize donation line to 'Buy me a beer:'

README.md

@@ -121,5 +121,5 @@ DeepSeek, DeepSeek-V4-Flash-Vision-Exp, 2026.
 
 ---
 
-If this fixture saved you an afternoon of debugging, you can buy me a beer:
+Buy me a beer:
 **BTC** `bc1q5ayht3fxhj0v95fk0z8l2f6900g3awdsw5842p`