fileSize static method
Formats file size in bytes to a human-readable format (e.g., "12.5 MB").
Implementation
static String fileSize(int bytes) {
if (bytes < 1024) return '$bytes B';
if (bytes < 1024 * 1024) return '${(bytes / 1024).toStringAsFixed(1)} KB';
if (bytes < 1024 * 1024 * 1024) return '${(bytes / (1024 * 1024)).toStringAsFixed(1)} MB';
return '${(bytes / (1024 * 1024 * 1024)).toStringAsFixed(1)} GB';
}