it is possible to make a plugin who can launch the "cmd.exe" and run commands from the construct 2 app?
That is not possible.
Web developers having access to external program on a users computer except for those with a registered URL protocol handler is not possible.
Could you imagine visiting the wrong website with a command to run a batch script that would delete your files? It would be crazy.
For all intensive purposes your browser is sandboxed and anything outside of the sandbox is off limits.