Shopify App Bridge and Google Apps Scripts - not possible?

Question

I'm trying to build a Shopify embedded app using Google Apps Scripts and am having trouble getting the library to provide any kind of response. I have built an app with App Bridge before using regular JS / HTML / CSS, but I am wondering if there is something that is preventing it from working with Apps Scripts creating the HTML output.

function doGet(e) {
// I was experimenting with this and it throws a 'window not defined' error
//  eval(UrlFetch('https://unpkg.com/@shopify/[email protected]/umd/index.js').getContentText());

  return HtmlService.createTemplateFromFile('Page')
      .evaluate().setXFrameOptionsMode(HtmlService.XFrameOptionsMode.ALLOWALL);  
}

function include(filename) {
  return HtmlService.createHtmlOutputFromFile(filename)
      .getContent();
}

And in my Page.html I am including Javascript.html like:

<?!= include('JavaScript'); ?>

In Javascript.html I try to initialize the app but the App Bridge library doesn't respond at all in the console. I've also tried to render a ResourcePicker, for example, and nothing happens.

<script src="https://unpkg.com/@shopify/[email protected]/umd/index.js"></script>

<script>
      var AppBridge = window['app-bridge'];
      var actions = AppBridge.actions;
      var createApp = AppBridge.default;
      var app = createApp({
        apiKey: {my api key},
        shopOrigin: {shopOrigin}
              });
...