feat(theme,interfaces): Introduce a global theming system and unify menu/tab interfaces; migrate components to use themeDefaultStyles and update APIs accordingly

ts_web/elements/dees-progressbar/dees-progressbar.ts

@@ -16,6 +16,7 @@ import {
 } from '@design.estate/dees-element';
 
 import * as domtools from '@design.estate/dees-domtools';
+import { themeDefaultStyles } from '../00theme.js';
 
 @customElement('dees-progressbar')
 export class DeesProgressbar extends DeesElement {
@@ -29,8 +30,10 @@ export class DeesProgressbar extends DeesElement {
   accessor percentage = 0;
 
   public static styles = [
+    themeDefaultStyles,
     cssManager.defaultStyles,
     css`
+      /* TODO: Migrate hardcoded values to --dees-* CSS variables */
       :host {
         color: ${cssManager.bdTheme(colors.bright.text, colors.dark.text)};
       }