feat(docs): add welcome screen with animated logo

Introduce a new welcome screen that automatically redirects first-time visitors from the homepage. The screen features an animated "Easy Vibe" logo with three color themes (ocean, rainbow, sunset) that cycle through a drawing animation. Users can click anywhere to enter the main site.

The welcome screen includes:
- A JSON file containing SVG path data for the animated logo
- A Vue component with gradient backgrounds and smooth animations
- Logic to detect first-time visitors using localStorage
- Integration into the existing VitePress theme structure
- Updated navigation to exclude the welcome page from sidebar controls
- Modified homepage logic to redirect to welcome screen on first visit

docs/.vitepress/theme/index.js

@@ -9,6 +9,7 @@ import { useRoute, useData } from 'vitepress'
 import './style.css'
 import Layout from './Layout.vue'
 import HomeFeatures from './components/HomeFeatures.vue'
+import WelcomeScreen from './components/WelcomeScreen.vue'
 import NavGrid from './components/NavGrid.vue'
 import NavCard from './components/NavCard.vue'
 import CategoryIndex from './components/CategoryIndex.vue'
@@ -846,6 +847,7 @@ export default {
   enhanceApp({ app }) {
     app.use(ElementPlus)
     app.component('HomeFeatures', HomeFeatures)
+    app.component('WelcomeScreen', WelcomeScreen)
     app.component('NavGrid', NavGrid)
     app.component('NavCard', NavCard)
     app.component('CategoryIndex', CategoryIndex)