electerm: Import unsafe bookmark data could lead to unsafe operation when click local type bookmark

electerm is an open-sourced terminal/ssh/sftp/telnet/serialport/RDP/VNC/Spice/ftp client. In 3.8.8 and earlier, there is persistent local-pty code execution via imported bookmarks or compromised sync targets. Affects users who import bookmark JSON files or who have electerm sync configured (gist/WebDAV). The attacker can inject exec* fields or global config to cause remote code to run when a bookmark is opened or when sync is applied.