fix: syntax error in colab notebook

Author: yuqi20000915

selfagent/build_colab.ipynb

@@ -28,7 +28,8 @@
     "# 1. 安装 Node.js\n",
     "!curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash -\n",
     "!sudo apt-get install -y nodejs\n",
-    "print(f\"Node: {!node -v}\")"
+    "!node -v\n",
+    "print(\"✅ Node.js 安装完成\")"
    ],
    "execution_count": null,
    "outputs": []