feat: use Tiktokenizer to count tokens

package.json

@@ -17,6 +17,7 @@
     "@chakra-ui/icons": "^2.0.17",
     "@chakra-ui/react": "^2.5.1",
     "@chakra-ui/system": "^2.5.5",
+    "@dqbd/tiktoken": "^1.0.6",
     "@emotion/react": "^11.10.6",
     "@emotion/styled": "^11.10.6",
     "@next/font": "13.1.6",
@@ -29,6 +30,7 @@
     "formidable": "^2.1.1",
     "framer-motion": "^9.0.6",
     "gpt-token-utils": "^1.2.0",
+    "graphemer": "^1.4.0",
     "hyperdown": "^2.4.29",
     "immer": "^9.0.19",
     "jsonwebtoken": "^9.0.0",