fix(runtime): tokenize context compaction budget

package.json

@@ -43,6 +43,7 @@
     "electron-log": "5.4.3",
     "electron-updater": "6.8.3",
     "framer-motion": "12.36.0",
+    "js-tiktoken": "1.0.21",
     "react": "19.2.4",
     "react-dom": "19.2.4",
     "react-markdown": "^10.1.0",