feat(toc): add Table of Contents scroll highlighting (#738)

* feat(toc): add Table of Contents scroll highlighting

- Introduced a new toc.css file for styling the Table of Contents with active link highlighting.
- Implemented toc-scroll.js to manage scroll behavior and link activation based on viewport visibility.
- Updated core.html to include the new JavaScript file and ensure proper loading of the Table of Contents functionality.

* chore: lower root heading font weight for TOC

* chore: run `task css`

* chore: update dependencies in package.json and package-lock.json to version 4.1.11 for @tailwindcss/postcss and tailwindcss, and update @jridgewell packages to latest versions

package.json

@@ -6,10 +6,10 @@
     "build": "hugo --gc --minify --themesDir=../.. --source=exampleSite"
   },
   "devDependencies": {
-    "@tailwindcss/postcss": "^4.1.8",
+    "@tailwindcss/postcss": "^4.1.11",
     "postcss-cli": "^11.0.1",
     "prettier": "^3.5.3",
     "prettier-plugin-go-template": "^0.0.15",
-    "tailwindcss": "^4.1.8"
+    "tailwindcss": "^4.1.11"
   }
 }