Fix offline banner stuck after DevTools network toggle

The online event could fire between page load and useEffect registering
its listener, leaving isOffline stuck at true despite navigator.onLine
being true. A zero-delay setTimeout after listener registration re-syncs
from navigator.onLine, covering that race.

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

src/components/pwa-register.tsx

@@ -4,10 +4,7 @@ import { useEffect, useState } from "react";
 
 export function PwaRegister() {
   const [showUpdate, setShowUpdate] = useState(false);
-  // Lazy init reads navigator.onLine on the client; SSR always returns false.
-  const [isOffline, setIsOffline] = useState(
-    () => typeof navigator !== "undefined" && !navigator.onLine
-  );
+  const [isOffline, setIsOffline] = useState(false);
   const [mutationFailed, setMutationFailed] = useState(false);
 
   useEffect(() => {
@@ -15,6 +12,10 @@ export function PwaRegister() {
     const handleOnline = () => setIsOffline(false);
     window.addEventListener("offline", handleOffline);
     window.addEventListener("online", handleOnline);
+    // Re-sync after listeners are registered in case the online/offline event
+    // fired between page load and this effect running (e.g. DevTools toggle).
+    const syncId = setTimeout(() => setIsOffline(!navigator.onLine), 0);
+
 
     if (!("serviceWorker" in navigator)) {
       return () => {
@@ -48,6 +49,7 @@ export function PwaRegister() {
     navigator.serviceWorker.addEventListener("message", handleMessage);
 
     return () => {
+      clearTimeout(syncId);
       window.removeEventListener("offline", handleOffline);
       window.removeEventListener("online", handleOnline);
       navigator.serviceWorker.removeEventListener(