feat(game): add persistent bush-wall breakthroughs

docs/UI_STYLE.md

@@ -127,12 +127,12 @@ are not MVP requirements.
 - Player zoom and pan controls are not part of the MVP.
 - Use different colors plus labels, outlines, shapes, or icons to distinguish
   player ownership and object types.
-- A server `blocked` rejection shakes the visible maze opposite the attempted
-  cardinal movement for at most 340 ms, without text or spike notice. A
-  `rate_limited` rejection darkens and blurs only the maze for at most 520 ms,
-  also without text. Repeated feedback restarts one bounded effect of each type.
-- Reduced-motion mode replaces the blocked shake with one static directional
-  border cue; rate-limit feedback remains immediate and non-animated.
+- Server-approved breakthrough impacts one through four bend the visible bush
+  wall with four increasing restrained stages and no text or spike notice. A
+  fifth accepted move is reflected by a permanent textured trampled-bush gap.
+  The browser uses one restartable impact timer and no generated particles.
+  `rate_limited` still darkens and blurs only the maze for at most 520 ms.
+- Reduced-motion mode uses static deformation and the same trampled-gap state.
 
 ## 8. Responsive behavior