ce12e7f976
Both blueprint-sweep bind faults (wrong-kind axis value; an open param
no axis covers) must print prose in the unknown-axis sibling's register
— axis name, kind/knob specifics, a --list-axes pointer — never the raw
Debug structs KindMismatch{..}/MissingKnob(..). Exit stays 2. Fails on
the Debug leakage present today, not on scaffolding.
refs #247