cncli sign does not emit anymore the proof but only its hash

**Describe the bug**
I am not really sure if this is a bug or my misinterpretation, but I noticed a changes in the `cncli sign` command about that is put in output, and apparently it does not print anymore the proof but its hash.

previously it was putting the 80 bytes of the proof encoded as hex, not it prints 64 bytes of the hash,
I do not understand how that signature hash could be for example being used by `cncli verify`.

Start by reproducing the `cncli sign` and `cncli verify` commands and compare the current output with the reported 80-byte proof versus 64-byte hash. Trace the sign and verify entry points to determine the expected exchanged value; done when signing produces output that verification can use correctly.

Written by the indexing model from the issue text.