feat: add Vue.js WebUI — YesPlayMusic-inspired SPA with all pages and components

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/src/main.ts

@@ -0,0 +1,10 @@
+import { createApp } from 'vue';
+import { createPinia } from 'pinia';
+import App from './App.vue';
+import router from './router/index.js';
+import './styles/global.scss';
+
+const app = createApp(App);
+app.use(createPinia());
+app.use(router);
+app.mount('#app');