Fix brand theme application and add comprehensive translations

- Fixed theme not being reflected on gallery and admin login pages
- Created GlobalThemeProvider to apply themes globally
- Updated gallery and admin login pages to use dynamic CSS variables
- Added complete translations for all admin sections in English and German:
  - Notifications management
  - Event view and creation
  - Photo upload functionality
  - Category management
  - Archive page view
  - Analytics dashboard
  - Branding and theme settings
  - System settings
  - CMS page management
  - Email configuration
- Fixed admin photo management display issues
- Fixed photo upload category assignment
- Added password reset functionality for galleries
- Improved error handling and user feedback

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

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

frontend/src/components/MaintenanceWrapper.tsx

@@ -0,0 +1,59 @@
+import React, { useEffect } from 'react';
+import { useLocation } from 'react-router-dom';
+import { useQuery } from '@tanstack/react-query';
+import { MaintenanceMode } from './MaintenanceMode';
+import { useMaintenanceMode } from '../contexts/MaintenanceContext';
+import { setMaintenanceModeCallback, api, getAuthToken } from '../config/api';
+
+interface MaintenanceWrapperProps {
+  children: React.ReactNode;
+}
+
+export const MaintenanceWrapper: React.FC<MaintenanceWrapperProps> = ({ children }) => {
+  const location = useLocation();
+  const { isMaintenanceMode, setMaintenanceMode } = useMaintenanceMode();
+  
+  // Check if current route is admin route
+  const isAdminRoute = location.pathname.startsWith('/admin');
+  const hasAdminAuth = !!getAuthToken(true);
+
+  // Register the maintenance mode callback
+  useEffect(() => {
+    setMaintenanceModeCallback((enabled: boolean) => {
+      setMaintenanceMode(enabled);
+    });
+  }, [setMaintenanceMode]);
+
+  // Check maintenance mode on mount and when location changes
+  useQuery({
+    queryKey: ['maintenance-check', location.pathname],
+    queryFn: async () => {
+      try {
+        // Make a lightweight request to check maintenance status
+        await api.get('/api/public/settings');
+        // If successful, maintenance mode is off
+        setMaintenanceMode(false);
+        return { maintenance: false };
+      } catch (error: any) {
+        if (error.response?.status === 503) {
+          // Only set maintenance mode for non-admin routes or unauthenticated admin routes
+          if (!isAdminRoute || !hasAdminAuth) {
+            setMaintenanceMode(true);
+            return { maintenance: true };
+          }
+        }
+        return { maintenance: false };
+      }
+    },
+    staleTime: 30000, // Check every 30 seconds
+    retry: false, // Don't retry on failure
+    enabled: (!isAdminRoute || !hasAdminAuth) && !isMaintenanceMode, // Don't check if already in maintenance
+  });
+
+  // Show maintenance page if in maintenance mode and not on admin route with auth
+  if (isMaintenanceMode && (!isAdminRoute || !hasAdminAuth)) {
+    return <MaintenanceMode />;
+  }
+
+  return <>{children}</>;
+};