Some config changes before grunt migration

webpack.config.js

@@ -13,8 +13,7 @@ if (process.env.RC_STATIC_DIR) {
 // doing it this way because it seems that plugin via grunt does not pick up .babelrc
 let babelRCOptions = {
     "assumptions": {
-        "setPublicClassFields": true,
-        "privateFieldsAsProperties": true
+        "setPublicClassFields": true
     },
     "presets": [
         ["@babel/preset-env", {
@@ -33,7 +32,8 @@ let babelRCOptions = {
 module.exports = {
     mode: 'production',
     optimization: {
-        minimize: false  // Let grunt-terser handle minification to avoid double-minification
+        minimize: false,  // Disable webpack minification - grunt-terser handles final minification
+        usedExports: false,  // Disable tree-shaking - it breaks Lit's re-exports
     },
     // Tell Webpack which file kicks off our app.
     entry: {