feat(audio,site): calm santoor default music + card-fan logo site redesign

- audio: default background music is now the santoor track (calm Persian),
  rebuilt as a real plucked-santoor loop — fast metallic attack, shimmer
  overtones, soft tonic drone, longer Dastgah-e-Shur phrase
- site: marketing logo is now the app's card-fan icon (Logo.tsx + icon.svg);
  hero features the big logo with gold halo, floating suit motifs, and
  polished section dividers

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

site/app/page.tsx

@@ -2,6 +2,7 @@ import {
   Users, Bot, Trophy, Gift, MessageCircle, Globe, ShieldCheck, Zap, Crown, Star,
 } from "lucide-react";
 import { DownloadButtons } from "@/components/DownloadButtons";
+import { Logo } from "@/components/Logo";
 import { BRAND } from "@/lib/site";
 
 const FEATURES = [
@@ -29,8 +30,22 @@ export default function Home() {
   return (
     <>
       {/* Hero */}
-      <section className="felt card-pattern">
+      <section className="felt card-pattern relative overflow-hidden">
+        {/* decorative card suits floating in the backdrop */}
+        <span className="suit pointer-events-none absolute right-[6%] top-16 text-8xl">♠</span>
+        <span className="suit pointer-events-none absolute left-[8%] top-40 text-7xl">♥</span>
+        <span className="suit pointer-events-none absolute left-[14%] bottom-12 text-6xl">♦</span>
+        <span className="suit pointer-events-none absolute right-[12%] bottom-20 text-7xl">♣</span>
+
         <div className="mx-auto max-w-6xl px-4 py-16 text-center sm:py-24">
+          {/* card-fan brand mark */}
+          <div className="relative mx-auto mb-8 grid h-40 w-40 place-items-center sm:h-48 sm:w-48">
+            <div className="gold-halo absolute inset-0 rounded-full" />
+            <div className="float-y relative">
+              <Logo size={160} glow />
+            </div>
+          </div>
+
           <span className="inline-flex items-center gap-1.5 rounded-full glass px-3 py-1 text-xs text-gold-soft">
             <Star size={13} /> بازی حکمِ ایرانی، حرفه‌ای‌تر از همیشه
           </span>
@@ -48,7 +63,7 @@ export default function Home() {
 
           <div className="mx-auto mt-12 grid max-w-3xl gap-3 sm:grid-cols-3">
             {STATS.map((s) => (
-              <div key={s.label} className="glass rounded-2xl px-4 py-4">
+              <div key={s.label} className="glass rounded-2xl px-4 py-4 transition hover:border-gold/40">
                 <s.icon className="mx-auto text-teal" size={22} />
                 <div className="mt-2 text-sm font-bold text-cream">{s.label}</div>
                 <div className="text-xs text-cream/55">{s.value}</div>
@@ -66,6 +81,7 @@ export default function Home() {
         <p className="mx-auto mt-3 max-w-xl text-center text-cream/60">
           همهٔ چیزی که یک بازی حکم بی‌نقص لازم دارد، در یک اپ.
         </p>
+        <div className="rule-gold mx-auto mt-6 max-w-xs" />
         <div className="mt-10 grid gap-5 sm:grid-cols-2 lg:grid-cols-3">
           {FEATURES.map((f) => (
             <div key={f.title} className="glass rounded-2xl p-6 transition hover:border-gold/40">
@@ -97,6 +113,9 @@ export default function Home() {
 
       {/* Final CTA */}
       <section className="mx-auto max-w-4xl px-4 py-16 text-center">
+        <div className="mx-auto mb-6 w-fit">
+          <Logo size={64} glow />
+        </div>
         <h2 className="text-3xl font-black sm:text-4xl">
           همین حالا <span className="gold-text">حکم</span> را شروع کن
         </h2>