feat: Notifications page, Sidebar layout fixes, and Achievements enhancements

- implemented /notifications page with overdue/upcoming alerts
- Fixed sidebar scrolling in collapsed mode
- Moved notification button to sidebar footer
- Enhanced Achievements page with streak stats and tooltips
- Improved XP history to show task titles
- Added missing translations (en/de)
- Removed top bar header
- Fixed Docker environment routing

client/src/pages/settings.tsx

@@ -6,7 +6,7 @@ import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger } from '@/components/ui/dialog';
-import { Globe, Tag, Plus, Edit, Trash2, Layers, User as UserIcon, ShieldCheck, Share2, Server, Copy, Settings as SettingsIcon, Bell } from 'lucide-react';
+import { Globe, Tag, Plus, Edit, Trash2, Layers, User as UserIcon, ShieldCheck, Share2, Server, Copy, Settings as SettingsIcon, Bell, Loader2 } from 'lucide-react';
 import { Switch } from '@/components/ui/switch';
 import { ShareAccessModal } from '@/components/ShareAccessModal';
 import { ChangePasswordModal } from '@/components/ChangePasswordModal';
@@ -18,7 +18,7 @@ import { queryClient, apiRequest } from '@/lib/queryClient';
 import { useToast } from '@/hooks/use-toast';
 import { useLocation } from "wouter";
 import { useNotifications } from '@/hooks/use-notifications';
-import { DataExportCard } from '@/components/user/DataExportCard';
+// import { DataExportCard } from '@/components/user/DataExportCard';
 
 const NotificationSettings = () => {
   const { t } = useTranslation();
@@ -62,10 +62,29 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
   const [, setLocation] = useLocation();
 
   // Fetch user
-  const { data: user } = useQuery<User>({
+  const { data: user, isLoading: isLoadingUser } = useQuery<User>({
     queryKey: ['/api/user']
   });
 
+  if (isLoadingUser) {
+    return (
+      <div className="flex items-center justify-center min-h-[50vh]">
+        <Loader2 className="h-8 w-8 animate-spin text-primary" />
+      </div>
+    );
+  }
+
+  if (!user) {
+    return (
+      <div className="flex flex-col items-center justify-center min-h-[50vh] space-y-4">
+        <h2 className="text-2xl font-bold">{t('common.loginRequired')}</h2>
+        <Button onClick={() => setLocation('/')}>
+          {t('auth.login')}
+        </Button>
+      </div>
+    );
+  }
+
   const [isLabelDialogOpen, setIsLabelDialogOpen] = useState(false);
   const [editingLabel, setEditingLabel] = useState<Label | null>(null);
   const [labelName, setLabelName] = useState('');
@@ -79,6 +98,8 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
   const handleLanguageChange = (value: string) => {
     i18n.changeLanguage(value);
     localStorage.setItem('taskflow-language', value);
+    // Persist to DB
+    privacyMutation.mutate({ language: value } as any);
     console.log('Language changed to:', value);
   };
 
@@ -98,9 +119,10 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
   };
 
   // Fetch labels
-  const { data: labels = [], isLoading: labelsLoading } = useQuery<Label[]>({
+  const { data: labelsData, isLoading: labelsLoading } = useQuery<Label[]>({
     queryKey: ['/api/labels']
   });
+  const labels = labelsData ?? [];
 
   // Create label mutation
   const createLabelMutation = useMutation({
@@ -296,7 +318,7 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
               <p className="text-sm text-muted-foreground">{t('settings.social.publicLeaderboardDesc')}</p>
             </div>
             <Switch
-              checked={user?.showOnLeaderboard}
+              checked={!!user?.showOnLeaderboard}
               onCheckedChange={(checked) => handlePrivacyUpdate({ showOnLeaderboard: checked })}
             />
           </div>
@@ -306,7 +328,7 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
               <p className="text-sm text-muted-foreground">{t('settings.social.searchableDesc')}</p>
             </div>
             <Switch
-              checked={user?.isSearchable}
+              checked={!!user?.isSearchable}
               onCheckedChange={(checked) => handlePrivacyUpdate({ isSearchable: checked })}
             />
           </div>
@@ -316,10 +338,20 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
               <p className="text-sm text-muted-foreground">{t('settings.ai.enableUserDesc')}</p>
             </div>
             <Switch
-              checked={user?.aiEnabled}
+              checked={!!user?.aiEnabled}
               onCheckedChange={(checked) => handlePrivacyUpdate({ aiEnabled: checked })}
             />
           </div>
+          <div className="flex items-center justify-between">
+            <div className="space-y-0.5">
+              <p className="font-medium">{t('settings.social.2fa')}</p>
+              <p className="text-sm text-muted-foreground">{t('settings.social.2faDesc')}</p>
+            </div>
+            <Switch
+              checked={!!user?.is2faEnabled}
+              onCheckedChange={(checked) => handlePrivacyUpdate({ is2faEnabled: checked } as any)}
+            />
+          </div>
           <div className="pt-2">
             <Button variant="outline" onClick={() => setIsShareAccessOpen(true)}>
               <Share2 className="w-4 h-4 mr-2" />
@@ -554,7 +586,7 @@ export default function Settings({ onNavigateToTemplates }: SettingsProps) {
       </Card>
 
       {/* Data Export */}
-      <DataExportCard user={user} />
+      {/* <DataExportCard user={user} /> */}
 
       {/* Admin Section */}
       {