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

js/components/listing-card.js

@@ -4,8 +4,6 @@ import { getXmrRates, formatPrice as formatCurrencyPrice } from '../services/cur
 import { auth } from '../services/auth.js'
 import { favoritesService } from '../services/favorites.js'
 
-let cachedRates = null
-
 class ListingCard extends HTMLElement {
     static get observedAttributes() {
         return ['listing-id', 'title', 'price', 'currency', 'location', 'image', 'owner-id', 'payment-status', 'status', 'priority']
@@ -53,10 +51,7 @@ class ListingCard extends HTMLElement {
     }
 
     async loadRates() {
-        if (!cachedRates) {
-            cachedRates = await getXmrRates()
-        }
-        this.rates = cachedRates
+        this.rates = await getXmrRates()
     }
 
     attributeChangedCallback() {