Initial scaffold: wages app

Full wage cost reporting app — weekly/monthly views, rolling 12-week/12-month
history, budget management, Workforce API sync with SSE backfill, net sales
via forecasting public API, department filter, CSV export.

Co-Authored-By: Claude Sonnet 4.6 <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: '/wages/',
+  plugins: [
+    react(),
+    VitePWA({
+      registerType: 'autoUpdate',
+      manifest: {
+        name: 'Wage Costs',
+        short_name: 'Wages',
+        start_url: '/wages/',
+        scope: '/wages/',
+        display: 'standalone',
+        theme_color: '#065f46',
+        background_color: '#065f46',
+        icons: [
+          { src: '/wages/icons/icon-192.png', sizes: '192x192', type: 'image/png' },
+          { src: '/wages/icons/icon-512.png', sizes: '512x512', type: 'image/png' },
+        ],
+      },
+      workbox: {
+        navigateFallback: '/wages/index.html',
+        navigateFallbackDenylist: [/\/api\//],
+        globPatterns: ['**/*.{js,css,html,ico,png,svg}'],
+      },
+    }),
+  ],
+})