fix(frontend): Anwendungen-Gruppe bei Start eingeklappt, Dashboard-Klick resettet auf Home-Tab

- AppLayout: appsOpen initial false (Anwendungen immer eingeklappt beim Laden)
- DashboardPage: useLocation + useEffect auf location.key → setzt activeTab
  auf 'home' bei jedem Navigations-Klick auf Dashboard in der Sidebar

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

packages/frontend/src/shell/AppLayout.tsx

@@ -125,7 +125,7 @@ export function AppLayout() {
     isModuleEnabled('deals') ||
     isModuleEnabled('pipelines');
   const [crmOpen, setCrmOpen] = useState(true);
-  const [appsOpen, setAppsOpen] = useState(true);
+  const [appsOpen, setAppsOpen] = useState(false);
   const [collapsed, setCollapsed] = useState(() => {
     return localStorage.getItem('sidebar-collapsed') === 'true';
   });

packages/frontend/src/shell/DashboardPage.tsx

@@ -1,4 +1,5 @@
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
+import { useLocation } from 'react-router-dom';
 import { useAuth } from '../auth/AuthContext';
 import { WeatherWidget } from '../components/WeatherWidget';
 import { AnalogClock } from '../components/AnalogClock';
@@ -698,8 +699,14 @@ function ComingSoonTab({ label }: { label: string }) {
 
 export function DashboardPage() {
   const { user } = useAuth();
+  const location = useLocation();
   const [activeTab, setActiveTab] = useState<DashboardTab>('home');
 
+  // Immer auf Home-Tab springen wenn Dashboard-NavLink geklickt wird
+  useEffect(() => {
+    setActiveTab('home');
+  }, [location.key]);
+
   return (
     <div>
       {/* Tab-Leiste */}