docs: add companies frontmatter, schema, and rendering in badges & appendix pages

apps/docs/content/(03-hierarchical)/tree-dfs/226_invert-binary-tree.mdx

@@ -9,6 +9,10 @@ topics:
   - { name: "Binary Tree", slug: "binary-tree" }
 video: "OnSn2XEQ4MY"
 issue: "https://github.com/prdlk/leetcode/issues/96"
+companies:
+  - { name: "Microsoft", period: "Thirty Days", frequency: 57.2 }
+  - { name: "Google", period: "Thirty Days", frequency: 29 }
+  - { name: "Meta", period: "Six Months", frequency: 32.7 }
 sidebar:
   label: 'Invert Binary Tree'
   badge: 'Easy'