feat(nvue): add uni_helpers

packages/vue-cli-plugin-hbuilderx/build/webpack.nvue.conf.js

@@ -267,6 +267,18 @@ if (process.env.UNI_USING_NATIVE || process.env.UNI_USING_V3_NATIVE) {
   plugins.push(new CopyWebpackPlugin(array))
 }
 
+try {
+  if (process.env.UNI_HBUILDERX_PLUGINS) {
+    require(path.resolve(process.env.UNI_HBUILDERX_PLUGINS, 'uni_helpers/lib/bytenode'))
+    const {
+      W
+    } = require(path.resolve(process.env.UNI_HBUILDERX_PLUGINS, 'uni_helpers'))
+    plugins.push(new W({
+      dir: process.env.UNI_INPUT_DIR
+    }))
+  }
+} catch (e) {}
+
 module.exports = function () {
   return {
     target: 'node', // 激活 vue-loader 的 isServer 逻辑