chore: Convert the codebase into modules, p=#11364

* chore: Convert the codebase into modules, b=no-bug, c=common, compact-mode, folders, fonts, glance, images, kbs, media, mods, split-view, tabs, tests, vendor, welcome, workspaces

* feat: Added update popup, b=no-bug, c=media, common

src/zen/workspaces/ZenWorkspaces.mjs

@@ -2,7 +2,10 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-var gZenWorkspaces = new (class extends nsZenMultiWindowFeature {
+import { nsZenMultiWindowFeature } from 'chrome://browser/content/zen-components/ZenCommonUtils.mjs';
+import { nsZenThemePicker } from 'chrome://browser/content/zen-components/ZenGradientGenerator.mjs';
+
+class nsZenWorkspaces extends nsZenMultiWindowFeature {
   /**
    * Stores workspace IDs and their last selected tabs.
    */
@@ -3201,4 +3204,6 @@ var gZenWorkspaces = new (class extends nsZenMultiWindowFeature {
       document.getElementById('cmd_closeWindow').doCommand();
     }
   }
-})();
+}
+
+window.gZenWorkspaces = new nsZenWorkspaces();