Imps reinforce walls next to claimed ground (heroes avoid them, ~10x slower to break)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lang/en.lang

@@ -273,3 +273,8 @@ newgame.width = Map width
 newgame.height = Map height
 newgame.start = Start
 newgame.info = {0} portal(s), {1} guarded treasure cave(s)
+
+# ---- walls, towers, torture
+job.reinforce = Reinforcing a wall
+tile.reinforced = Reinforced wall
+tile.reinforced_info = heroes can hardly break through