fix: PWA icon, robust socket.io reconnect, faster real-time sync

src/app/app/page.tsx

@@ -20,7 +20,7 @@ import { Dialog, DialogContent, DialogHeader, DialogTitle } from '@/components/u
 import { JournalView } from '@/components/journal/journal-view'
 import { jsPDF } from 'jspdf'
 import { Lock, Unlock, Eye, AlertTriangle, WifiOff } from 'lucide-react'
-import { getSocket } from '@/lib/socket'
+import { getSocket, setSocketRoom } from '@/lib/socket'
 import { CustomDragLayer } from '@/components/map/custom-drag-layer'
 import { addToSyncQueue, flushSyncQueue, getSyncQueue, isOnline as checkOnline } from '@/lib/offline-sync'
 
@@ -507,27 +507,31 @@ export default function AppPage() {
   const socketRef = useRef<any>(null)
   const prevProjectIdRef = useRef<string | null>(null)
 
-  // Throttled socket broadcast for near-real-time sync (1.5s instead of 10s auto-save)
+  // Throttled socket broadcast for near-real-time sync
   const lastEmitRef = useRef(0)
   const emitTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const currentProjectRef = useRef(currentProject)
+  useEffect(() => { currentProjectRef.current = currentProject }, [currentProject])
+
   const broadcastFeatures = useCallback((feats: DrawFeature[]) => {
-    if (!socketRef.current || !currentProject?.id || !isEditingByMe) return
+    const proj = currentProjectRef.current
+    if (!socketRef.current || !proj?.id || !isEditingByMeRef.current) return
     const now = Date.now()
     const emit = () => {
       socketRef.current?.emit('features-updated', {
-        projectId: currentProject!.id,
+        projectId: proj!.id,
         features: feats,
       })
       lastEmitRef.current = Date.now()
     }
-    // Throttle: emit at most every 1.5 seconds
-    if (now - lastEmitRef.current > 1500) {
+    // Throttle: emit at most every 800ms for snappier sync
+    if (now - lastEmitRef.current > 800) {
       emit()
     } else {
       if (emitTimerRef.current) clearTimeout(emitTimerRef.current)
-      emitTimerRef.current = setTimeout(emit, 1500 - (now - lastEmitRef.current))
+      emitTimerRef.current = setTimeout(emit, 800 - (now - lastEmitRef.current))
     }
-  }, [currentProject?.id, isEditingByMe])
+  }, [])
   const isEditingByMeRef = useRef(false)
 
   // Keep ref in sync with state
@@ -546,6 +550,7 @@ export default function AppPage() {
       socket.emit('leave-project', prevProjectIdRef.current)
     }
     socket.emit('join-project', currentProject.id)
+    setSocketRoom(currentProject.id)
     prevProjectIdRef.current = currentProject.id
 
     // Listen for features changes from other clients (only apply if NOT the editor)