fix: improve error handling in Wikipedia image provider

- Enhanced the queryAuthorInfo function to handle missing license name and URL gracefully.
- Added debug logging to provide insights when license information is not found, defaulting to 'Unknown' for license name and an empty string for license URL.
- This change improves the robustness of the image provider by preventing failures due to missing metadata.

internal/imageprovider/wikipedia.go

@@ -280,12 +280,18 @@ func (l *wikiMediaProvider) queryAuthorInfo(reqID, thumbnailURL string) (*wikiMe
 
 	licenseName, err := extMetadata.GetString("LicenseShortName", "value")
 	if err != nil {
-		return nil, fmt.Errorf("failed to get license name from extmetadata: %w", err)
+		if l.debug {
+			log.Printf("[%s] Debug: License name not found, using 'Unknown'", reqID)
+		}
+		licenseName = "Unknown"
 	}
 
 	licenseURL, err := extMetadata.GetString("LicenseUrl", "value")
 	if err != nil {
-		return nil, fmt.Errorf("failed to get license URL from extmetadata: %w", err)
+		if l.debug {
+			log.Printf("[%s] Debug: License URL not found, using empty string", reqID)
+		}
+		licenseURL = ""
 	}
 
 	artistHref, err := extMetadata.GetString("Artist", "value")