feat: initial commit — local services (backend + manager dashboard + waiter PWA)

Includes all work to date:
- local_backend: FastAPI backend with products, orders, tables, shifts, cloud sync
- manager_dashboard: React manager UI with product/category management, reports, settings
- waiter_pwa: React PWA for waiter devices
- Category reparent endpoint and UI
- Waiter domain: local_ip sent on heartbeat, waiter_domain persisted from cloud response
- QR code modal in AppInfoTab for waiter domain
- Product form: number input spinners removed, category pre-selected on new product
- Category row: count badge moved to far right

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

waiter_pwa/src/api/client.js

@@ -0,0 +1,26 @@
+import axios from 'axios'
+
+const client = axios.create({ baseURL: '' })
+
+client.interceptors.request.use(config => {
+  const token = localStorage.getItem('token')
+  if (token) config.headers.Authorization = `Bearer ${token}`
+  return config
+})
+
+client.interceptors.response.use(
+  res => res,
+  err => {
+    if (!err.response) {
+      window.dispatchEvent(new Event('backend-offline'))
+    } else if (err.response.status === 401) {
+      // Token expired or user blocked — force logout
+      localStorage.removeItem('token')
+      localStorage.removeItem('savedUsername')
+      window.location.href = '/login'
+    }
+    return Promise.reject(err)
+  }
+)
+
+export default client