Remove HyperMD and fix validation task

package.json

@@ -9,22 +9,21 @@
   "dependencies": {
     "@atlaskit/pragmatic-drag-and-drop": "^1.5.0",
     "@atlaskit/pragmatic-drag-and-drop-hitbox": "^1.0.3",
+    "@codemirror/lang-markdown": "^6.3.2",
     "@iconify/vue": "^4.3.0",
     "@lezer/highlight": "^1.2.1",
     "@markdoc/markdoc": "^0.5.1",
     "@nuxtjs/color-mode": "^3.5.2",
     "@nuxtjs/sitemap": "^7.2.5",
     "@nuxtjs/tailwindcss": "^6.13.1",
-    "@types/codemirror": "^5.60.15",
     "@vueuse/gesture": "^2.0.0",
     "@vueuse/math": "^12.7.0",
     "@vueuse/nuxt": "^12.7.0",
-    "codemirror": "5.65.18",
+    "codemirror": "^6.0.1",
     "drizzle-orm": "^0.39.3",
     "hast": "^1.0.0",
     "hast-util-heading": "^3.0.0",
     "hast-util-heading-rank": "^3.0.0",
-    "hypermd": "^0.3.11",
     "lodash.capitalize": "^4.2.1",
     "mdast-util-find-and-replace": "^3.0.2",
     "nodemailer": "^6.10.0",