perf: Replace JSDOM with cheerio to fix OOM in link checker

- Switch from JSDOM to cheerio for HTML parsing
- Cheerio is much lighter and faster (already a dependency)
- Fixes CI failure: JavaScript heap out of memory
- Remove jsdom and @types/jsdom dependencies

Author: bobbyonmagic

package.json

@@ -124,7 +124,6 @@
     "@tailwindcss/postcss": "^4.1.18",
     "@tailwindcss/typography": "0.5.19",
     "@types/js-yaml": "^4.0.9",
-    "@types/jsdom": "^28.0.0",
     "@types/node": "^25.2.3",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
@@ -136,7 +135,6 @@
     "eslint-config-prettier": "^10.1.8",
     "eslint-plugin-prettier": "^5.5.5",
     "fast-glob": "^3.3.3",
-    "jsdom": "^28.1.0",
     "postcss": "^8.5.6",
     "prettier": "^3.8.1",
     "sharp": "^0.34.5",