In the thread here: Is the Signal messenger integration still a thing? it is mentioned, that it is possible to use the Signal Messenger REST API and link to your existing phone number already registered with Signal. This would be very useful, so one does not have to get a spare mobile number for every Home Assistant / Signal API installation…
Can anyone point me in the right direction for this? @fjakkarin hints at a command line interface that allows this, but I have not been able to figure out how to proceed?