getMediaPath method
Returns the local file path for a message's media, or null if the file doesn't exist on disk.
Implementation
Future<String?> getMediaPath(String messageId) async {
final dir = await _getMessageMediaDir(messageId);
final msgDir = Directory(dir);
if (!await msgDir.exists()) return null;
final files = await msgDir.list().toList();
if (files.isEmpty) return null;
// Return the first (and typically only) file in the directory
return files.first.path;
}