Initial scaffold: tablet-checkin app

Staff-push guest check-in tablet. Fastify backend + React/Vite frontend,
three-tier auth (staff JWT, terminal API key, kiosk cookie), NewBook
integration via bookings_get/guests_update/bookings_update, pdfkit-based
regcard generation, marketing opt-in with Sendy/Mailchimp adapters.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/vite.config.ts

@@ -0,0 +1,31 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import { VitePWA } from 'vite-plugin-pwa'
+
+export default defineConfig({
+  base: '/tablet-checkin/',
+  plugins: [
+    react(),
+    VitePWA({
+      registerType: 'autoUpdate',
+      manifest: {
+        name: 'Tablet Check-In',
+        short_name: 'Check-In',
+        start_url: '/tablet-checkin/',
+        scope: '/tablet-checkin/',
+        display: 'standalone',
+        theme_color: '#be123c',
+        background_color: '#be123c',
+        icons: [
+          { src: '/tablet-checkin/icons/icon-192.png', sizes: '192x192', type: 'image/png' },
+          { src: '/tablet-checkin/icons/icon-512.png', sizes: '512x512', type: 'image/png' },
+        ],
+      },
+      workbox: {
+        navigateFallback: '/tablet-checkin/index.html',
+        navigateFallbackDenylist: [/\/api\//],
+        globPatterns: ['**/*.{js,css,html,ico,png,svg}'],
+      },
+    }),
+  ],
+})