Fix mobile responsiveness and implement enhanced theme system

- Fixed mobile gallery login box sizing and layout
- Fixed header button layout for mobile screens
- Fixed duplicate logo issue on logout
- Fixed '0' rendering when upload button is hidden
- Fixed horizontal scrolling on small screens

- Implemented comprehensive theme system with gallery layouts
- Added 6 different gallery layouts: Grid, Masonry, Carousel, Timeline, Hero, Mosaic
- Created enhanced theme customizer with layout selection
- Added theme presets for different event types
- Updated event creation with theme preview and customization
- Fixed all TypeScript compilation errors

- Added missing translation keys for create event page
- Added translations for theme customization features

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

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

frontend/src/components/gallery/GalleryView.tsx

@@ -6,7 +6,7 @@ import { useTranslation } from 'react-i18next';
 import { Button, SkeletonGalleryGrid, Skeleton } from '../common';
 import { useGalleryAuth, useTheme } from '../../contexts';
 import { useGalleryPhotos, useDownloadAllPhotos } from '../../hooks/useGallery';
-import { PhotoGrid } from './PhotoGrid';
+import { PhotoGridWithLayouts } from './PhotoGridWithLayouts';
 import { ExpirationBanner } from './ExpirationBanner';
 import { CountdownTimer } from './CountdownTimer';
 import { GalleryLayout } from './GalleryLayout';
@@ -226,23 +226,25 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
       onDownloadAll={handleDownloadAll}
       isDownloading={downloadAllMutation.isPending}
       headerExtra={
-        <>
-          {daysUntilExpiration <= 1 && daysUntilExpiration > 0 && (
-            <CountdownTimer expiresAt={event.expires_at} className="mr-4" />
-          )}
-          {event.allow_user_uploads && (
-            <Button
-              variant="outline"
-              size="md"
-              leftIcon={<Upload className="w-4 h-4" />}
-              onClick={() => setShowUploadModal(true)}
-              className="mr-2 text-sm sm:text-base"
-            >
-              <span className="hidden sm:inline">{t('upload.uploadPhotos')}</span>
-              <span className="sm:hidden">{t('common.upload')}</span>
-            </Button>
-          )}
-        </>
+        (daysUntilExpiration <= 1 && daysUntilExpiration > 0) || event.allow_user_uploads ? (
+          <>
+            {daysUntilExpiration <= 1 && daysUntilExpiration > 0 && (
+              <CountdownTimer expiresAt={event.expires_at} className="mr-2" />
+            )}
+            {event.allow_user_uploads && (
+              <Button
+                variant="outline"
+                size="sm"
+                leftIcon={<Upload className="w-4 h-4" />}
+                onClick={() => setShowUploadModal(true)}
+                className="flex-1 sm:flex-initial"
+              >
+                <span className="hidden sm:inline">{t('upload.uploadPhotos')}</span>
+                <span className="sm:hidden">{t('common.upload')}</span>
+              </Button>
+            )}
+          </>
+        ) : null
       }
     >
       {/* Expiration Banner */}
@@ -267,7 +269,7 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
 
         {/* Photo Grid */}
         <div className="mt-6">
-          <PhotoGrid photos={filteredPhotos} slug={slug} categoryId={selectedCategoryId} />
+          <PhotoGridWithLayouts photos={filteredPhotos} slug={slug} categoryId={selectedCategoryId} />
         </div>
       </div>