feat: UI: update vite config (#86)

frontend/package.json

@@ -2,6 +2,7 @@
   "name": "cloudflare_temp_email",
   "version": "0.0.0",
   "private": true,
+  "type": "module",
   "scripts": {
     "dev": "vite",
     "build": "vite build -m prod --emptyOutDir",

frontend/vite.config.js

@@ -3,6 +3,7 @@ import { fileURLToPath, URL } from 'node:url'
 import { defineConfig } from 'vite'
 import vue from '@vitejs/plugin-vue'
 import { VitePWA } from 'vite-plugin-pwa'
+import { splitVendorChunkPlugin } from 'vite';
 
 // https://vitejs.dev/config/
 export default defineConfig({
@@ -11,6 +12,7 @@ export default defineConfig({
   },
   plugins: [
     vue(),
+    splitVendorChunkPlugin(),
     VitePWA({
       registerType: 'autoUpdate',
       devOptions: {