Performance: i18n Lazy Loading, Bundle-Größe halbiert

- i18n lädt EN/SR Übersetzungen nur bei Bedarf
- Hauptbundle von 356KB auf 179KB reduziert (~50%)
- Entfernt modulepreload für nicht-kritische Chunks
- Nur react-vendor und i18n-vendor werden vorgeladen

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/i18n/index.ts

@@ -3,9 +3,19 @@ import i18n from 'i18next';
 import { initReactI18next } from 'react-i18next';
 import LanguageDetector from 'i18next-browser-languagedetector';
 
+// Only load German synchronously (default language)
 import translationDE from './locales/de';
-import translationEN from './locales/en';
-import translationSR from './locales/sr';
+
+// Lazy load other languages when needed
+const loadLanguage = async (lng: string) => {
+    if (lng === 'en' && !i18n.hasResourceBundle('en', 'translation')) {
+        const { default: translationEN } = await import('./locales/en');
+        i18n.addResourceBundle('en', 'translation', translationEN, true, true);
+    } else if (lng === 'sr' && !i18n.hasResourceBundle('sr', 'translation')) {
+        const { default: translationSR } = await import('./locales/sr');
+        i18n.addResourceBundle('sr', 'translation', translationSR, true, true);
+    }
+};
 
 i18n
     .use(LanguageDetector)
@@ -14,19 +24,21 @@ i18n
         resources: {
             de: {
                 translation: translationDE
-            },
-            en: {
-                translation: translationEN
-            },
-            sr: {
-                translation: translationSR
             }
         },
-        fallbackLng: 'en',
-        supportedLngs: ['en', 'de', 'sr'],
+        fallbackLng: 'de',
+        supportedLngs: ['de', 'en', 'sr'],
         interpolation: {
             escapeValue: false
         }
     });
 
+// Load language bundle when language changes
+i18n.on('languageChanged', loadLanguage);
+
+// Load initial language if not German
+if (i18n.language && i18n.language !== 'de') {
+    loadLanguage(i18n.language);
+}
+
 export default i18n;