fix(frontend): render-loop in Tasks/Reports/Communication behoben — usePluginToolbarStore wurde ohne Selector destrukturiert; jedes Store-Update re-renderte alle Seiten inkl. registerItems-Effektkette (Maximum update depth in Tests sichtbar). Selektor-Pattern wie Dms/Mail/Calendar/ContactsList

frontend/src/pages/Communication.tsx

@@ -755,7 +755,8 @@ export function CommunicationPage() {
   const [loading, setLoading] = useState(true);
   const [showNewChat, setShowNewChat] = useState<ConversationCategory | null>(null);
   const [mobileView, setMobileView] = useState<'list' | 'chat'>('list');
-  const { registerItems, unregisterPlugin } = usePluginToolbarStore();
+  const registerItems = usePluginToolbarStore((s) => s.registerItems);
+  const unregisterPlugin = usePluginToolbarStore((s) => s.unregisterPlugin);
 
   const loadConversations = useCallback(async () => {
     try {

frontend/src/pages/Reports.tsx

@@ -60,7 +60,8 @@ interface DownloadEntry {
 export function ReportsPage() {
   const { t } = useTranslation();
   const toast = useToast();
-  const { registerItems, unregisterPlugin } = usePluginToolbarStore();
+  const registerItems = usePluginToolbarStore((s) => s.registerItems);
+  const unregisterPlugin = usePluginToolbarStore((s) => s.unregisterPlugin);
 
   // Data hooks
   const { data: templates = [], isLoading: templatesLoading } = useReportTemplates();

frontend/src/pages/Tasks.tsx

@@ -220,7 +220,8 @@ function TaskDetail({ task, onEdit, onDelete, onStatusChange }: TaskDetailProps)
 export function TasksPage() {
   const { t } = useTranslation();
   const toast = useToast();
-  const { registerItems, unregisterPlugin } = usePluginToolbarStore();
+  const registerItems = usePluginToolbarStore((s) => s.registerItems);
+  const unregisterPlugin = usePluginToolbarStore((s) => s.unregisterPlugin);
 
   const [page, setPage] = useState(1);
   const [filter, setFilter] = useState<TaskFilter>({});