message: doc: fix storybook webpack config
diff: const webpack = require("webpack");
  const CopyPlugin = require("copy-webpack-plugin");
  -module.exports = {
  +module.exports = ({ config, mode }) => ({
  + ...config,
  externals: {
  + ...config.externals,
  cesium: "Cesium",
  },
  module: {
  + ...config.module,
  rules: [
  + ...config.module.rules,
  {
  test: /\.tsx?$/,
  exclude: /node_modules/,
  use: "ts-loader",
  },
  {
  - test: /.(glb|jpg|png|pnts)$/,
  + test: /.(glb|pnts)$/,
  use: "file-loader",
  },
  ],
  },
  plugins: [
  + ...config.plugins,
  new webpack.DefinePlugin({
  CESIUM_BASE_URL: JSON.stringify("/cesium"),
  }),
  + ...(mode === "PRODUCTION"
  + ? []
  + : [
  new CopyPlugin([
  {
  from: "node_modules/cesium/Build/CesiumUnminified",
  to: "cesium",
  },
  ]),
  + ]),
  ],
  resolve: {
  - extensions: [".js", ".ts", ".tsx"],
  + ...config.resolve,
  + extensions: [...config.resolve.extensions, ".ts", ".tsx"],
  },
  -};
  +});
  