fix: lightbox watermark loading, white label translations, and dynamic footer year

- Fix watermarked images not opening in lightbox (add /api prefix to photo URLs)
- Add i18n translations for 'White Label' and 'Hide Powered by' branding settings
- Add complete logo customization translations (EN and DE)
- Replace hardcoded © 2024 with dynamic current year in footer
- Use company name from settings in default footer text

frontend/src/components/gallery/GalleryLayout.tsx

@@ -444,7 +444,7 @@ export const GalleryLayout: React.FC<GalleryLayoutProps> = ({
             </p>
           )}
           <p className="text-xs sm:text-sm text-neutral-500">
-            {brandingSettings?.footer_text || '© 2024 Your Company. All rights reserved.'}
+            {brandingSettings?.footer_text || `© ${new Date().getFullYear()}${brandingSettings?.company_name ? ` ${brandingSettings.company_name}` : ''}. All rights reserved.`}
             {!brandingSettings?.hide_powered_by && (
               <> | Powered by <span className="font-semibold">PicPeak</span></>
             )}

frontend/src/components/gallery/GalleryView.tsx

@@ -203,7 +203,7 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
         company_name: settingsData.branding_company_name || '',
         company_tagline: settingsData.branding_company_tagline || '',
         support_email: settingsData.branding_support_email || '',
-        footer_text: settingsData.branding_footer_text || '© 2024 Your Company. All rights reserved.',
+        footer_text: settingsData.branding_footer_text || '',
         watermark_enabled: settingsData.branding_watermark_enabled || false,
         logo_url: settingsData.branding_logo_url || null,
         logo_size: settingsData.branding_logo_size || 'medium',
@@ -385,7 +385,7 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
     if (watermarkEnabled) {
       photos = photos.map(photo => ({
         ...photo,
-        url: `/gallery/${slug}/photo/${photo.id}`
+        url: `/api/gallery/${slug}/photo/${photo.id}`
       }));
     }