Add HTML & Markdown preview in dashboard and revise pages

package.json

@@ -13,6 +13,7 @@
     "body-parser": "^1.20.2",
     "connect-flash": "^0.1.1",
     "cors": "^2.8.5",
+    "dompurify": "^3.2.6",
     "dotenv": "^16.4.5",
     "ejs": "^3.1.10",
     "exceljs": "^4.4.0",
@@ -20,7 +21,9 @@
     "express-session": "^1.18.0",
     "form-data": "^4.0.3",
     "fs-extra": "^11.2.0",
+    "jsdom": "^26.1.0",
     "mammoth": "^1.9.1",
+    "marked": "^16.0.0",
     "multer": "^2.0.0",
     "pdf-parse": "^1.1.1",
     "uuid": "^10.0.0"