fix: resolve multiple UI issues in admin panel

- Fixed dropdown menu visibility in events table by using fixed positioning
- Fixed double /api prefix in settings upload endpoints (favicon, watermark)
- Fixed thumbnail display in hero image selection by properly handling API paths
- Removed unnecessary console.log statements
- Added proper cleanup for dropdown on scroll/resize events

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

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

frontend/src/components/common/AuthenticatedImage.tsx

@@ -62,9 +62,14 @@ export const AuthenticatedImage: React.FC<AuthenticatedImageProps> = ({
         let imageUrl = src;
         
         // Build full URL for the image
-        const fullImageUrl = imageUrl.startsWith('/') ? buildResourceUrl(imageUrl) : imageUrl;
+        // For API paths that start with /admin, we need to prepend /api
+        const fullImageUrl = imageUrl.startsWith('/admin') 
+          ? buildResourceUrl(`/api${imageUrl}`)
+          : imageUrl.startsWith('/') 
+          ? buildResourceUrl(imageUrl) 
+          : imageUrl;
         
-        console.log('Fetching authenticated image:', fullImageUrl);
+        // console.log('Fetching authenticated image:', fullImageUrl);
         const response = await fetch(fullImageUrl, {
           headers: {
             'Authorization': `Bearer ${token}`