style: unify all empty states to shared .empty-state class across all modules

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/pages/contacts.js

@@ -134,9 +134,15 @@ function renderList() {
 
   if (!contacts.length) {
     container.innerHTML = `
-      <div class="contacts-empty">
-        <i data-lucide="users" style="width:48px;height:48px;color:var(--color-text-disabled);margin-bottom:var(--space-3);" aria-hidden="true"></i>
-        <div style="font-size:var(--text-base);font-weight:600;">Keine Kontakte gefunden</div>
+      <div class="empty-state">
+        <svg class="empty-state__icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" aria-hidden="true">
+          <path d="M17 21v-2a4 4 0 0 0-4-4H5a4 4 0 0 0-4 4v2"/>
+          <circle cx="9" cy="7" r="4"/>
+          <path d="M23 21v-2a4 4 0 0 0-3-3.87"/>
+          <path d="M16 3.13a4 4 0 0 1 0 7.75"/>
+        </svg>
+        <div class="empty-state__title">Noch keine Kontakte</div>
+        <div class="empty-state__description">Neue Kontakte über den + Button hinzufügen.</div>
       </div>
     `;
     if (window.lucide) lucide.createIcons();