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/00group-appui/dees-appui-view/dees-appui-view.demo.ts

@@ -0,0 +1,30 @@
+import { html } from '@design.estate/dees-element';
+
+export const demoFunc = () => html`
+  <dees-appui-view
+    .viewConfig=${{
+      id: 'demo-view',
+      name: 'Demo View',
+      description: 'A demonstration view',
+      iconName: 'lucide:home',
+      tabs: [
+        {
+          key: 'overview',
+          iconName: 'lucide:lineChart',
+          action: () => console.log('Overview tab'),
+          content: html`<div style="padding: 20px;">Overview Content</div>`
+        },
+        {
+          key: 'details',
+          iconName: 'lucide:fileText',
+          action: () => console.log('Details tab'),
+          content: html`<div style="padding: 20px;">Details Content</div>`
+        }
+      ],
+      menuItems: [
+        { key: 'General', action: () => console.log('General') },
+        { key: 'Advanced', action: () => console.log('Advanced') },
+      ]
+    }}
+  ></dees-appui-view>
+`;