feat(webapp): add legacy build for older browser

www/webapp/package.json

@@ -22,6 +22,7 @@
     "vuetify": "^2.7.0"
   },
   "devDependencies": {
+    "@vitejs/plugin-legacy": "^4.1.1",
     "@vitejs/plugin-vue2": "^2.2.0",
     "eslint": "^8.45.0",
     "eslint-import-resolver-alias": "^1.1.2",

www/webapp/vite.config.js

@@ -3,6 +3,7 @@ import {defineConfig} from 'vite'
 import {resolve} from 'node:path';
 import Components from 'unplugin-vue-components/vite'
 import {VuetifyResolver} from 'unplugin-vue-components/resolvers'
+import legacy from '@vitejs/plugin-legacy'
 import vue from '@vitejs/plugin-vue2'
 
 export default defineConfig({
@@ -14,6 +15,7 @@ export default defineConfig({
         Components({
             resolvers: [VuetifyResolver()],
         }),
+        legacy(), // Build for old browser.
     ],
     server: {
         port: 8080,