os.execv on Windows joins its arguments with spaces and quotes nothing, so
only the interpreter and script path (quoted by hand) survived a restart.
Any other argument with a space, e.g. --browser-profile "Profile 1", was
split in two and ComfyUI failed to start with 'unrecognized arguments'.
Build the command in one helper, manager_util.build_restart_command, used by
both the reboot endpoint and the prestartup restart. On Windows every entry
is quoted with subprocess.list2cmdline; other platforms are unchanged.
Fixes#3339
