Calmer shop with payment choice, step-by-step phone back, sound/haptics that reach the phone, live streak flame

- Shop: subscription perks shown once (each card repeated them, «۳ سوال در روز» twice), plans as selectable
  rows with one big buy button, prices as «۷۹۸ هزار تومان», a single clear status card for subscribers.
  Checkout inside the Bazaar app offers «کارتِ بانکی» (default) or «کافه‌بازار» for packs with a SKU;
  «به‌زودی در بازار» is gone. The gateway opens in the phone browser; status refreshes on return.
- Back button: every back-able level (open sheet, pushed screen, non-home tab, shop list) owns exactly one
  history entry created right after the tap; back closes the sheet, then the screen, then returns to Home,
  then leaves the app. (A re-pushed trap is skipped by Chrome's history intervention.)
- Sound: AudioContext unlocked on the first touch (it was created after a network wait, which WebView/Safari
  keep muted); softer notes, option tick, finish fanfare, streak whoosh. Haptics through the new
  TadrisinoAndroid.vibrate bridge when the APK has it, navigator.vibrate otherwise.
- Streak: animated flame with lit / at-risk (grey) / frozen (ice) states on Home and the streak screen,
  a companion reminder when the streak is at risk or frozen, and a full-screen «روزِ پیاپی» celebration
  after the first lesson of the day (needs backend 9024c6b: streak.activeToday / lost).
- Lessons: intro/example text with inline «۱. … ۲. …» renders as a numbered list (2,250 of 4,469 texts).
- Quiz: duplicate React key on the answer bubble fixed.
- android/MainActivity.kt: vibrate bridge and mediaPlaybackRequiresUserGesture=false. Not built; needs the
  next APK from the signing owner.

Checked in headless Chrome against the local backend (shop as a subscriber with the Bazaar bridge stubbed,
back sequences, quiz → streak celebration, frozen state). Not checked on a real phone or in the APK.

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

src/components/Sheet.tsx

@@ -1,6 +1,7 @@
 import { useEffect, type ReactNode } from 'react';
 import { AnimatePresence, motion, useDragControls } from 'motion/react';
 import { X } from 'lucide-react';
+import { useBackStep } from '@/nav/Navigator';
 
 /**
  * برگه‌ای که از پایین بالا می‌آید؛ با زدنِ پس‌زمینه، Escape، یا کشیدنِ دستگیره/سرِ برگه به پایین بسته می‌شود.
@@ -18,6 +19,8 @@ export function Sheet({
   children: ReactNode;
 }) {
   const drag = useDragControls();
+  // دکمه‌ی برگشتِ گوشی اول برگه را می‌بندد، نه صفحه‌ی زیرش را.
+  useBackStep(open, onClose);
   useEffect(() => {
     if (!open) return;
     const onKey = (e: KeyboardEvent) => e.key === 'Escape' && onClose();