feat: Initialize VitePress documentation system with multi-language content, custom theme, and assets.

docs/.vitepress/theme/index.ts

@@ -0,0 +1,13 @@
+import DefaultTheme from 'vitepress/theme'
+import Layout from './Layout.vue'
+import Icon from './components/Icon.vue'
+import 'flag-icons/css/flag-icons.min.css'
+import './style.css'
+
+export default {
+  extends: DefaultTheme,
+  Layout: Layout,
+  enhanceApp({ app }) {
+    app.component('Icon', Icon)
+  }
+}