Enhance email templates with clickable links, branding, and improved styling

- Add clickable gallery links in all email templates
- Include application logo in email header and footer (custom or PicPeak default)
- Redesign emails with professional styling matching gallery login page
  - Gray background with white content box
  - PicPeak green header with centered logo
  - Clean typography and proper spacing
  - Responsive design for mobile devices
  - Styled call-to-action buttons
  - Footer with branding and copyright
- Update email processor to fetch branding settings dynamically
- Use proper API URLs for logo images in emails

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

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

frontend/src/components/GlobalThemeProvider.tsx

@@ -21,9 +21,12 @@ export const GlobalThemeProvider: React.FC<GlobalThemeProviderProps> = ({ childr
     staleTime: 5 * 60 * 1000, // Cache for 5 minutes
   });
 
-  // Apply global theme when settings are loaded
+  // Apply global theme when settings are loaded (but not on gallery pages)
   useEffect(() => {
-    if (!themeAppliedRef.current && settingsData?.theme_config) {
+    // Skip if we're on a gallery page - gallery pages handle their own themes
+    const isGalleryPage = window.location.pathname.includes('/gallery/');
+    
+    if (!themeAppliedRef.current && settingsData?.theme_config && !isGalleryPage) {
       themeAppliedRef.current = true;
       setTheme(settingsData.theme_config);
     }