docs: redesign table of content (#12647)

* implement toc

* added to projects

* fixes and adapt for references

* added product frontmatter

* remove action menu from 404 pages

www/apps/book/package.json

@@ -18,6 +18,7 @@
     "@mdx-js/react": "^3.1.0",
     "@medusajs/icons": "2.8.3",
     "@next/mdx": "15.3.1",
+    "@stefanprobst/rehype-extract-toc": "^3.0.0",
     "clsx": "^2.1.0",
     "docs-ui": "*",
     "docs-utils": "*",
@@ -26,6 +27,7 @@
     "react-dom": "rc",
     "rehype-mdx-code-props": "^2.0.0",
     "rehype-slug": "^6.0.0",
+    "remark-frontmatter": "^5.0.0",
     "remark-rehype-plugins": "*"
   },
   "devDependencies": {