feat: major dashboard & waiter PWA overhaul

- Manager dashboard: replaced monolithic DashboardTab/OperationsPage with new
  DashboardPage; added OrderDetailModal, ShiftDetailModal, DeleteConfirmModal,
  PaymentMethodModal; updated Sidebar routing and App navigation
- Reports: reworked WorkDaySummary, OrderHistory, ShiftsOverview with detail modals
- Backend routers: extended orders, reports, shifts, products, business_day endpoints;
  updated cloud_sync service
- Waiter PWA: refreshed app icons, improved ConnectionLostModal UX, updated
  TableCard, SSEContext, connectionStore; added useProductCache hook; vite config tweaks

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

waiter_pwa/src/context/SSEContext.jsx

@@ -1,10 +1,12 @@
 import { createContext, useContext, useCallback, useEffect, useRef } from 'react'
+import { useQueryClient } from '@tanstack/react-query'
 import useAuthStore from '../store/authStore'
 import useConnectionStore from '../store/connectionStore'
 import { useSSE } from '../hooks/useSSE'
 import db from '../db/posdb'
 import client from '../api/client'
 import { flushOfflinePayments } from '../services/offlinePayments'
+import { invalidateProductCache } from '../hooks/useProductCache'
 
 const SSEContext = createContext(null)
 
@@ -17,6 +19,7 @@ const HEARTBEAT_INTERVAL = 30_000
 export function SSEProvider({ children }) {
   const { token } = useAuthStore()
   const { setLost, setOnline } = useConnectionStore()
+  const queryClient = useQueryClient()
   const sseAlive = useRef(false)
   const heartbeatRef = useRef(null)
 
@@ -97,10 +100,14 @@ export function SSEProvider({ children }) {
         await snapshotTables()
         break
       }
+      case 'products_changed': {
+        invalidateProductCache(queryClient)
+        break
+      }
       default:
         break
     }
-  }, [snapshotTables])
+  }, [snapshotTables, queryClient])
 
   // ── SSE connection lifecycle ─────────────────────────────────────────────────
 
@@ -175,6 +182,32 @@ export function SSEProvider({ children }) {
     return () => window.removeEventListener('backend-offline', onBackendOffline)
   }, [])
 
+  // ── Wake-up handshake — fires when tab/app returns from background ────────────
+
+  useEffect(() => {
+    if (!token) return
+    async function onVisible() {
+      if (document.visibilityState !== 'visible') return
+      try {
+        await client.get('/api/system/health')
+        const currentStatus = useConnectionStore.getState().status
+        if (currentStatus === 'lost' || currentStatus === 'emergency' || currentStatus === 'reconnecting') {
+          setOnlineRef.current()
+          reconnect()
+          await fullRefresh()
+        } else if (!sseAlive.current) {
+          // SSE dropped silently while sleeping — re-establish quietly
+          reconnect()
+          await fullRefresh()
+        }
+      } catch {
+        if (!sseAlive.current) setLostRef.current()
+      }
+    }
+    document.addEventListener('visibilitychange', onVisible)
+    return () => document.removeEventListener('visibilitychange', onVisible)
+  }, [token, reconnect, fullRefresh])
+
   // ── Initial snapshot on login ─────────────────────────────────────────────────
 
   useEffect(() => {