Illusion Wall is castable: it was missing from the edge-target list

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>

packages/web/src/App.svelte

@@ -85,7 +85,7 @@
 
   const selectedDef = $derived(selectedCard ? cardDef(selectedCard.cardId) : null);
   const EDGE_CARDS = new Set([
-    "create-wall", "destroy-wall", "wall-of-fire", "waterwall",
+    "create-wall", "destroy-wall", "illusion-wall", "wall-of-fire", "waterwall",
     "pick-lock", "jam-lock", "remove-lock", "master-key", "dispel-creation",
     "warp-wand", "create-door", "stone-to-water",
   ]);