update claude.md

Author: svenvg93

CLAUDE.md

@@ -34,6 +34,10 @@ This application is a Laravel application and its main Laravel ecosystems packag
 - Stick to existing directory structure - don't create new base folders without approval.
 - Do not change the application's dependencies without approval.
 
+## Localization
+- Only create or update language files in the `lang/en` directory. Do not create or modify language files for other locales.
+- All translation strings should be added only to the English language files.
+
 ## Frontend Bundling
 - If the user doesn't see a frontend change reflected in the UI, it could mean they need to run `npm run build`, `npm run dev`, or `composer run dev`. Ask them.