feat(mobile): default push notifications to off

Per App Store guideline 4.5.4 + Apple HIG, the iOS notification
permission prompt should fire on user-initiated action, not opportunistically.
Previously the toggle defaulted to true and the prompt fired the moment
the desktop sent its first notification — reads as unsolicited.

Now the toggle defaults to false; the OS prompt only fires when the
user explicitly enables notifications in Settings → Notifications.
Also fixes a brief 'on' flash on the Notifications screen before the
saved preference loads.

Co-authored-by: Orca <help@stably.ai>

mobile/app/notifications.tsx

@@ -13,7 +13,7 @@ import { ensureNotificationPermissions } from '../src/notifications/mobile-notif
 export default function NotificationsScreen() {
   const router = useRouter()
   const insets = useSafeAreaInsets()
-  const [pushEnabled, setPushEnabled] = useState(true)
+  const [pushEnabled, setPushEnabled] = useState(false)
 
   useFocusEffect(
     useCallback(() => {

mobile/src/storage/preferences.ts

@@ -4,13 +4,18 @@ const PINS_PREFIX = 'orca:pins:'
 const PREFS_PREFIX = 'orca:prefs:'
 const NOTIF_KEY = 'orca:pushNotificationsEnabled'
 
+// Why: default-off so the iOS notification permission prompt never
+// fires until the user explicitly opts in via Settings → Notifications.
+// Apple's review guideline 4.5.4 and HIG both prefer user-initiated
+// permission prompts; default-on would fire the prompt the moment the
+// desktop sent its first notification, which can read as unsolicited.
 export async function loadPushNotificationsEnabled(): Promise<boolean> {
   try {
     const raw = await AsyncStorage.getItem(NOTIF_KEY)
-    if (raw === null) return true
+    if (raw === null) return false
     return raw === 'true'
   } catch {
-    return true
+    return false
   }
 }