feat(DateTimePicker): integrate flatpickr for enhanced date/time selection and theming

package.json

@@ -17,10 +17,10 @@
     "better-sqlite3": "^11.0.0",
     "concurrently": "^9.0.0",
     "cors": "^2.8.5",
-    "date-fns": "^4.1.0",
     "dotenv": "^16.4.0",
     "express": "^4.21.0",
     "express-rate-limit": "^7.5.1",
+    "flatpickr": "^4.6.13",
     "ioredis": "^5.10.0",
     "jsonwebtoken": "^9.0.0",
     "lucide-react": "^0.460.0",
@@ -29,7 +29,6 @@
     "pg": "^8.18.0",
     "rate-limit-redis": "^4.3.1",
     "react": "^18.3.0",
-    "react-datepicker": "^9.1.0",
     "react-dom": "^18.3.0",
     "react-hot-toast": "^2.4.0",
     "react-router-dom": "^6.28.0",