feat: Add Storage Explorer with CLI terminal, alias management, and file browser

- Add CLI terminal for executing mc commands from the web interface
  - Command history with up/down arrow navigation
  - Dark theme with monospace font
  - Auto-scroll output and loading states

- Add alias management page
  - List all MinIO aliases with connection status
  - Add, edit, delete aliases
  - Test connection functionality

- Add file browser for navigating bucket contents
  - Breadcrumb navigation (alias > bucket > path)
  - File/folder table with size, type, last modified
  - Upload files (drag-and-drop support)
  - Download, rename, delete operations
  - Create new folders
  - Multi-select for batch delete

Backend:
- New API routes: /api/terminal, /api/aliases, /api/browser
- Multer middleware for file uploads
- Extended minio.service.js with file operations

Frontend:
- New Explorer component with Aliases/Terminal tabs
- Zustand stores for terminal and explorer state
- i18n translations (English and German)

frontend/src/components/Layout/Layout.tsx

@@ -25,6 +25,7 @@ import {
   ChevronLeft as ChevronLeftIcon,
   Dashboard as DashboardIcon,
   Storage as StorageIcon,
+  FolderOpen as FolderOpenIcon,
   People as PeopleIcon,
   Policy as PolicyIcon,
   Assessment as AssessmentIcon,
@@ -55,6 +56,7 @@ const Layout: React.FC = () => {
   const navItems: NavItem[] = [
     { text: 'Dashboard', icon: <DashboardIcon />, path: '/', translationKey: 'navigation.dashboard' },
     { text: 'Buckets', icon: <StorageIcon />, path: '/buckets', translationKey: 'navigation.buckets' },
+    { text: 'Explorer', icon: <FolderOpenIcon />, path: '/explorer', translationKey: 'navigation.explorer' },
     { text: 'Users', icon: <PeopleIcon />, path: '/users', translationKey: 'navigation.users' },
     { text: 'Policies', icon: <PolicyIcon />, path: '/policies', translationKey: 'navigation.policies' },
     { text: 'Reports', icon: <AssessmentIcon />, path: '/reports', translationKey: 'navigation.reports' },
@@ -224,7 +226,7 @@ const Layout: React.FC = () => {
           {navItems.map((item) => (
             <ListItem key={item.text} disablePadding>
               <ListItemButton
-                selected={location.pathname === item.path}
+                selected={location.pathname === item.path || location.pathname.startsWith(item.path + '/')}
                 onClick={() => navigate(item.path)}
               >
                 <ListItemIcon>{item.icon}</ListItemIcon>