feat(manager): Part 2 — Online Orders page and sidebar integration

- connect_orders.py: add GET /api/connect/orders?status=active|history endpoints
- api/client.js: add getIncomingOrders, getActiveOrders, getOrderHistory,
  acceptOnlineOrder, rejectOnlineOrder, updateOnlineOrderStatus
- OnlineOrdersPage.jsx: three-tab page (Incoming / Active / History) with
  order cards, action buttons (accept/reject/status progression),
  20 s polling, SSE listener for online_order_received/updated events,
  and optimistic UI updates
- App.jsx: add /online-orders route
- Sidebar.jsx: add Online Orders nav item with red badge showing pending count,
  polling every 20 s independently of the page

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

manager_dashboard/src/api/client.js

@@ -23,3 +23,18 @@ client.interceptors.response.use(
 )
 
 export default client
+
+// ── Online Orders (Xenia Connect) ─────────────────────────────────────────────
+
+export const getIncomingOrders = () => client.get('/api/connect/orders/incoming')
+export const getActiveOrders   = () => client.get('/api/connect/orders?status=active')
+export const getOrderHistory   = () => client.get('/api/connect/orders?status=history')
+
+export const acceptOnlineOrder = (id) =>
+  client.post(`/api/connect/orders/${id}/accept`)
+
+export const rejectOnlineOrder = (id, reason) =>
+  client.post(`/api/connect/orders/${id}/reject`, { reason })
+
+export const updateOnlineOrderStatus = (id, status) =>
+  client.post(`/api/connect/orders/${id}/status`, { status })