nice, looks good, can you explain why this works now?

The signal.signal() function can be used to define your own handlers that are executed when a signal is received.

SIGINT is a standard handler that translates a keyboard interrupt

SIG_DFL ensures that ctrl+c is recognized to close the program

ok, also crosschecked SIG_DFL which essentially tells the kernel to handle SIGINT as is - which means that qt6 is disabling this behavior by default - ok, why not ;)

on the other side, I could test this successfully - think this should be good for now.

Could we also disable this behavior during runtime ? Means, as of now one could likely kill the nitrokeyapp during an update operation, which would brick the device - I am not sure if we should introduce this if this could happen...