Fix Vercel deploy: replace isomorphic-dompurify with sanitize-html

isomorphic-dompurify loads jsdom which depends on html-encoding-sniffer
-> @exodus/bytes (ESM-only). Vercel Serverless uses CJS require() so
this crashes all API routes with ERR_REQUIRE_ESM.

sanitize-html is pure Node.js with no DOM dependency.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: IMMINJU

package.json

@@ -61,7 +61,6 @@
     "drizzle-orm": "^0.45.1",
     "file-type": "^21.3.0",
     "formidable": "^3.5.4",
-    "isomorphic-dompurify": "^3.0.0",
     "lowlight": "^3.3.0",
     "lucide-react": "^0.562.0",
     "next": "16.1.1",
@@ -79,6 +78,7 @@
     "react-dom": "19.2.3",
     "react-email": "^5.2.5",
     "react-hook-form": "^7.71.1",
+    "sanitize-html": "^2.17.1",
     "sonner": "^2.0.7",
     "tailwind-merge": "^3.4.0",
     "tippy.js": "^6.3.7",
@@ -96,6 +96,7 @@
     "@types/nodemailer": "^7.0.5",
     "@types/react": "^19",
     "@types/react-dom": "^19",
+    "@types/sanitize-html": "^2.16.1",
     "@vitest/coverage-v8": "^4.0.18",
     "dotenv": "^17.2.3",
     "drizzle-kit": "^0.31.8",