feat: PWA setup + /app base path

- Landing page at /
- Vue app at /app (PWA installable)
- Added manifest.json for mobile install
- iOS + Android meta tags
- Updated router base path

vite.config.ts

@@ -4,6 +4,7 @@ import { resolve } from 'path'
 
 export default defineConfig({
   plugins: [vue()],
+  base: '/app/',
   resolve: {
     alias: {
       '@': resolve(__dirname, 'src'),