fix: security hardening + code quality improvements (401 retry limit, UUID crypto, debounce this-bug, deduplicate CSS/helpers, optimize SW precache)

js/components/error-boundary.js

@@ -73,13 +73,13 @@ export function setupGlobalErrorHandler() {
         
         // Don't show UI for script loading errors
         if (event.filename && event.filename.includes('.js')) {
-            showErrorToast(event.message || 'Ein Fehler ist aufgetreten')
+            showErrorToast(event.message || t('common.error'))
         }
     })
 
     window.addEventListener('unhandledrejection', (event) => {
         console.error('Unhandled promise rejection:', event.reason)
-        showErrorToast(event.reason?.message || 'Ein Fehler ist aufgetreten')
+        showErrorToast(event.reason?.message || t('common.error'))
     })
 
     // Offline/Online detection