roller: support private keys with leading 0x
==
::
%setkey
+ =? pk.config =((end [3 2] pk.config) '0x')
+ (rsh [3 2] pk.config)
?~ pk=(de:base16:mimes:html pk.config)
`state
[(get-nonce q.u.pk /nonce) state(pk q.u.pk)]
