Add debug logging for file preview errors

- Add console logging when setting preview proxy URL
- Enhance error handler to capture and log error event details
- Log current preview URL on load failure for debugging

components/FilePreviewModal.vue

@@ -158,7 +158,9 @@ const loadPreview = async () => {
     // For images and PDFs, use the proxy endpoint to avoid CORS issues
     if (isImage.value || isPdf.value) {
       // Use the proxy endpoint that serves the file directly
-      previewUrl.value = `/api/files/proxy-preview?fileName=${encodeURIComponent(props.file.name)}`;
+      const proxyUrl = `/api/files/proxy-preview?fileName=${encodeURIComponent(props.file.name)}`;
+      console.log('Setting preview URL to:', proxyUrl);
+      previewUrl.value = proxyUrl;
       // The loading state will be handled by the image/iframe onload event
     } else {
       throw new Error('File type does not support preview');
@@ -170,7 +172,9 @@ const loadPreview = async () => {
 };
 
 // Handle preview load error
-const handlePreviewError = () => {
+const handlePreviewError = (event: any) => {
+  console.error('Preview load error:', event);
+  console.error('Current preview URL:', previewUrl.value);
   error.value = 'Failed to load preview';
   loading.value = false;
 };