feat(app): scaffold Vue3 frontend (stage 1)

app-frontend/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "app-frontend",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@element-plus/icons-vue": "^2.3.2",
+    "axios": "^1.12.2",
+    "element-plus": "^2.11.3",
+    "pinia": "^3.0.3",
+    "socket.io-client": "^4.8.1",
+    "vue": "^3.5.24",
+    "vue-router": "^4.6.3"
+  },
+  "devDependencies": {
+    "@vitejs/plugin-vue": "^6.0.1",
+    "vite": "^7.2.4"
+  }
+}
+