The engine has always accepted it — edge target, line of sight to the
edge, open corridor only — but the client's EDGE_CARDS list never
included illusion-wall, so selecting it offered no clickable wall
lines and the card was simply uncastable. The LOS dimming that
appears alongside is correct and stays: placement requires sight of
the wall line, so the lit squares show where the shimmering can go.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>