fix: push-notification toggle in settings always showed as off

Never checked the browser's actual push subscription on mount — state
initialized to false unconditionally, so the button looked reset to
"Enable notifications" on every page load even when notifications were
genuinely still active. Now checks navigator.serviceWorker + getSubscription()
on mount and initializes from that.

apps/web/components/pwa/push-subscribe-button.tsx

@@ -1,13 +1,34 @@
 "use client";
 
-import { useState } from "react";
+import { useState, useEffect } from "react";
 import { Bell, BellOff } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { toast } from "sonner";
 
 export function PushSubscribeButton() {
   const [subscribed, setSubscribed] = useState(false);
-  const [loading, setLoading] = useState(false);
+  const [loading, setLoading] = useState(true);
+
+  // The button previously always started as "not subscribed" regardless of
+  // actual state — it never checked the browser's real push subscription on
+  // mount, so it looked reset every time this page loaded even when
+  // notifications were genuinely still enabled.
+  useEffect(() => {
+    let cancelled = false;
+    (async () => {
+      try {
+        if (!("serviceWorker" in navigator)) return;
+        const registration = await navigator.serviceWorker.ready;
+        const sub = await registration.pushManager.getSubscription();
+        if (!cancelled) setSubscribed(!!sub);
+      } catch {
+        // ignore — leave as not-subscribed if the check itself fails
+      } finally {
+        if (!cancelled) setLoading(false);
+      }
+    })();
+    return () => { cancelled = true; };
+  }, []);
 
   async function handleSubscribe() {
     if (Notification.permission === "denied") {