ci: add typescript capability and a11y linting

package.json

@@ -17,13 +17,16 @@
     "tailwindcss": "^4.2.1"
   },
   "devDependencies": {
+    "@astrojs/ts-plugin": "^1.10.6",
     "@eslint/js": "^10.0.1",
     "@markuplint/astro-parser": "^4.6.23",
     "@markuplint/ml-config": "^4.8.15",
+    "@typescript-eslint/parser": "^8.56.1",
     "cspell": "^9.7.0",
     "eslint": "^10.0.2",
     "eslint-config-prettier": "^10.1.8",
     "eslint-plugin-astro": "^1.6.0",
+    "eslint-plugin-jsx-a11y": "^6.10.2",
     "eslint-plugin-prettier": "^5.5.5",
     "markuplint": "^4.14.1",
     "postcss-html": "^1.8.1",