chore: Rename menu item Become → BeBetter

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: 2 people

config/_default/menus.en.toml

@@ -14,6 +14,6 @@
   weight = 30
 
 [[main]]
-  name = "Become"
+  name = "BeBetter"
   url = "https://howtobebetter.ai"
   weight = 40