Complete Settings page and fix TypeScript issues

- Create comprehensive SettingsPage with General, Storage, and Security tabs
- Add formatBytes method to settings service
- Update AdminSidebar to show real storage usage from backend
- Fix TypeScript errors with react-query v5 (isPending instead of isLoading)
- Remove unused imports and fix type imports
- Add Settings route to App.tsx
- Implement real-time storage monitoring in sidebar

🤖 Generated with [Claude Code](https://claude.ai/code)

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

frontend/src/pages/admin/AnalyticsPage.tsx

@@ -5,14 +5,13 @@ import {
   Users, 
   Eye,
   Download,
-  Globe,
   Smartphone,
   Monitor,
   Activity,
   RefreshCw,
   Tablet
 } from 'lucide-react';
-import { format, subDays, parseISO } from 'date-fns';
+import { format, parseISO } from 'date-fns';
 
 import { Button, Card, Loading } from '../../components/common';
 import { useQuery } from '@tanstack/react-query';