Smooth screen transitions: new screen waits hidden until its data arrives, no half-built flash

- Navigator stage: the next screen mounts hidden under the current one and is revealed only when its
  first data has arrived (ScreenGate held by useAsync/useGateHold), at most 450 ms; a thin top bar shows
  after 120 ms of waiting. Push slides from the left, back from the right, tabs only fade.
- Session cache (stale-while-revalidate) for screen GETs: revisited screens draw instantly.
- Home map and stats are fetched during the splash, so the first screen arrives complete.
- Entrance pop-ins (mascot, islands, lesson cards) run on first view only, not on every revisit.
- Shop status card shows placeholders instead of a wrong «نداری» while loading.
- Re-tapping the open tab scrolls to top instead of reloading; sheets close with a swipe down.
- Quiz: «۱ از ۴» instead of «۱/۴» (read as a fraction), varied praise, «N تا پشتِ هم درست»,
  growth-mindset copy after a weak round, zero-reward tiles hidden.
- Streak: a concrete next step when the streak is 0 or today is still empty.

Checked in headless Chrome against the local backend (frame captures at 150 ms and 700 ms latency,
rapid tab tapping, full quiz run). Not checked on a real phone or iOS Safari.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/screens/ProfileScreen.tsx

@@ -131,7 +131,7 @@ export function ProfileScreen({ onSignedOut }: { onSignedOut: () => void }) {
  * موعد روزها را روی هم می‌گذارد، پس نوار در ۱۰۰٪ بسته می‌شود. زدنِ کارت فروشگاه را باز می‌کند.
  */
 function SubscriptionCard({ onOpen }: { onOpen: () => void }) {
-  const status = useAsync(() => api.subscription.status(), []);
+  const status = useAsync(() => api.subscription.status(), [], { key: 'subscription-status' });
   const s = status.data;
   if (!s) return <div className="h-[132px] animate-pulse rounded-3xl bg-soft" />;
   const days = s.active ? daysLeft(s.expiresAt) : 0;