feat(player): reposition mobile player focal point

docs/UI_STYLE.md

@@ -113,8 +113,11 @@ are not MVP requirements.
 
 ## 7. Player map presentation
 
-- Keep the player near the center of the map viewport except where maze
-  boundaries prevent it.
+- Keep the portrait player horizontally centered at approximately 30% of the
+  usable map height, above the directional-pad hand zone. In compact landscape,
+  use the stable left-biased focal point in the largest unobstructed map area.
+  Recalculate it after resize and rotation without moving the authoritative
+  player away from its received `self` cell.
 - Render unknown space as a solid background. Never infer, retain, animate, or
   decorate maze geometry outside the server-provided visible projection.
 - Compute cell size from the current server projection and available map area.