- ProBoardDef.autoRun: after boot (+guestSetup) the VFS uploads itself
and the command runs, so a single Run click boots, uploads and starts
the user's script (same UX as compiled boards)
- ProBoardDef.guestHome: VFS home dir override ('/root' for guests that
log in as root); those boards drop the historic hello.sh sample
- upload sequence extracted to utils/piUpload (shared by the VFS panel
button and autoRun)
- serial monitor strips DEL/C0 control echoes (backspace showed tofu)
David Montero Crespo