Add PWA service worker (via vite plugin), use dynamic viewport units for interface size (improves mobile experience), replace default vue homepage with basic info

frontend/vite.config.js

@@ -3,12 +3,17 @@ import { fileURLToPath, URL } from 'node:url'
 import { defineConfig } from 'vite'
 import vue from '@vitejs/plugin-vue'
 import vueDevTools from 'vite-plugin-vue-devtools'
+import { VitePWA } from 'vite-plugin-pwa'
 
 // https://vite.dev/config/
 export default defineConfig({
   plugins: [
     vue(),
     vueDevTools(),
+    VitePWA({
+      registerType: 'autoUpdate',
+      devOptions: {enabled: true},
+    }),
   ],
   build: {
     sourcemap: true,