Subscription store, paywall on locked units, profile subscription bar, Tadrisino branding

- Store opens with two choices (subscription / question packs); 3- and 6-month cards
  show per-month price and saving.
- Units that need a subscription show a crown badge and open the store; a 402 from
  the quiz goes there too. «ادامه بده» skips locked units.
- Profile: subscription card with an animated days-left bar (planDurationDays).
- BrandMark (SVG) on splash, home header and footer; copyright footer; floating math
  glyphs on splash. CSS transform/opacity only; honours reduced motion.

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

src/styles/index.css

@@ -109,3 +109,13 @@
 /* ناحیه‌ی لمسِ بزرگ‌تر بدونِ تغییرِ ظاهر: دکمه‌های کوچکِ سربرگ (۲۸–۳۲ پیکسل) برای انگشت کوچک‌اند. */
 .hit { position: relative; }
 .hit::after { content: ''; position: absolute; inset: -7px -3px; }
+
+/* نوارِ اشتراک و نشانِ تدریسینو: فقط transform/opacity تا روی GPU بماند و روانی حفظ شود. */
+@keyframes bar-fill { from { transform: scaleX(0); } to { transform: scaleX(1); } }
+.bar-fill { transform-origin: right; animation: bar-fill 0.9s cubic-bezier(.2,.8,.2,1) both; }
+@keyframes shine { 0% { transform: translateX(120%); } 60%, 100% { transform: translateX(-220%); } }
+.shine { animation: shine 3.2s ease-in-out infinite; will-change: transform; }
+@keyframes spark { 0%, 100% { opacity: .25; transform: scale(.7); } 50% { opacity: 1; transform: scale(1); } }
+.spark { animation: spark 2.4s ease-in-out infinite; transform-box: fill-box; transform-origin: center; }
+@keyframes rise { 0% { transform: translateY(16px); opacity: 0; } 15%, 85% { opacity: .55; } 100% { transform: translateY(-110px); opacity: 0; } }
+.rise { animation: rise 7s linear infinite; will-change: transform, opacity; }