优化橡皮擦删除选区后的视觉效果

frontend/src/core/features/whiteboard/interaction/BoardInteractionManager.ts

@@ -768,6 +768,8 @@ export class BoardInteractionManager {
       this.board.removeElement(el.id)
       this.selectedIds.delete(el.id)
       this.updateRendererSelection()
+      // 擦除后清除悬停高亮
+      this.emit('eraser:hover', { eraserHoverElement: null })
     }
   }