docs: replace legacy line‑dot‑left‑horizontal icons with unified dot icon across docs

apps/docs/content/(03-hierarchical)/tree-bfs/102-binary-tree-level-order-traversal.mdx

@@ -1,7 +1,7 @@
 ---
 title: '102. Binary Tree Level Order Traversal'
 description: Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level)
-icon: line-dot-left-horizontal
+icon: dot
 sidebar:
   label: 'Binary Tree Level Order Traversal'
   badge: 'Medium'