Fix ebook scanner error handling for database queries

- Remove string-based error checking for no rows
- Use proper pgx.ErrNoRows comparison only
- Improve error handling consistency in processEbookFile function

internal/services/ebook_scanner.go

@@ -226,7 +226,7 @@ func (s *EbookScanner) processEbookFile(ctx context.Context, path string) error
 		}
 		fmt.Printf("Ebook already exists with same size, skipping: %s\n", path)
 		return nil // Skip if already exists and size matches
-	} else if err != pgx.ErrNoRows && !strings.Contains(err.Error(), "no rows") {
+	} else if err != pgx.ErrNoRows {
 		fmt.Printf("Database error checking ebook existence: %v\n", err)
 		// Some other error occurred
 		return fmt.Errorf("failed to check if ebook exists: %v", err)