- Wrap lesson label in span for mobile hiding
- Truncate module name with ellipsis if too long
- Hide "Lesson/Lektion" label on mobile, show only "1 / 3"
- Add lessonLabel i18n keys for EN/DE
- Create i18n.js module with EN/DE translations
- Add data-i18n attributes to index.html for dynamic text
- Update renderer.js to use translation functions
- Language switcher button replaces link to German page
- Stores preference in localStorage, detects browser language