feat(coming-soon): hard-lock the live curtain; closable only on local/dev hosts

The curtain was sessionStorage-dismissible everywhere. NODE_ENV can't tell the
live deploy from the local Docker site (both are prod builds), so gate on the
hostname instead: localhost + private LAN ranges (incl. 172.28.x) keep the
"view experimental (local)" close button; any public domain is hard-locked to
just the countdown. Starts the curtain up by default so the live site never
flashes a page before it mounts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/layout/ComingSoonOverlay.tsx

@@ -21,6 +21,25 @@ const faDigits = ["۰", "۱", "۲", "۳", "۴", "۵", "۶", "۷", "۸", "۹"];
 const fa = (n: number | string) =>
   String(n).replace(/[0-9]/g, (d) => faDigits[Number(d)]);
 
+/**
+ * Local/dev hosts may close the curtain; the live (public) site is hard-locked.
+ * NODE_ENV can't distinguish them — both local Docker and the deploy are prod
+ * builds — so we key off the hostname: localhost + private LAN ranges = local.
+ */
+function isLocalHost(): boolean {
+  if (typeof window === "undefined") return false;
+  const h = window.location.hostname;
+  return (
+    h === "localhost" ||
+    h === "127.0.0.1" ||
+    h === "0.0.0.0" ||
+    h.endsWith(".local") ||
+    /^10\./.test(h) ||
+    /^192\.168\./.test(h) ||
+    /^172\.(1[6-9]|2\d|3[01])\./.test(h) // 172.16–31.x (incl. the 172.28.x dev LAN)
+  );
+}
+
 const FEATURES = [
   { icon: "⚡", title: "رندر فوق‌سریع ویدیو", desc: "ویدیوهایتان را در چند دقیقه و در فضای ابری رندر کنید" },
   { icon: "💰", title: "هزینهٔ بسیار پایین", desc: "پرداخت بر اساس ثانیه؛ مقرون‌به‌صرفه‌تر از همیشه" },
@@ -49,14 +68,22 @@ function useCountdown(target: Date) {
 }
 
 export function ComingSoonOverlay() {
-  const [open, setOpen] = useState(false);
+  // Start UP so the live site never flashes the page before the curtain mounts.
+  const [open, setOpen] = useState(true);
+  // Only local/dev hosts get a way out; the live site stays locked.
+  const [canDismiss, setCanDismiss] = useState(false);
   const cd = useCountdown(LAUNCH);
 
   useEffect(() => {
-    // Show unless dismissed earlier this session.
     if (typeof window === "undefined") return;
+    const local = isLocalHost();
+    setCanDismiss(local);
+    if (local) {
+      // Local: respect a prior dismissal so dev navigation isn't blocked.
       const dismissed = sessionStorage.getItem(STORAGE_KEY);
       setOpen(dismissed !== "1");
+    }
+    // Live: no dismissal path — the curtain stays up, only the countdown shows.
   }, []);
 
   // Lock background scroll while the curtain is up.
@@ -198,20 +225,22 @@ export function ComingSoonOverlay() {
               ))}
             </div>
 
-            {/* CTA */}
+            {/* CTA — local/dev only; the live site has no way past the curtain. */}
+            {canDismiss && (
               <div className="mt-9">
                 <button
                   type="button"
                   onClick={dismiss}
                   className="group inline-flex items-center gap-2 rounded-full bg-gradient-to-l from-[#3ba7ff] to-[#a855f7] px-8 py-3.5 text-base font-bold text-white shadow-lg shadow-indigo-500/30 transition hover:scale-[1.03] hover:shadow-indigo-500/50"
                 >
-                مشاهدهٔ نسخهٔ آزمایشی
+                  مشاهدهٔ نسخهٔ آزمایشی (محلی)
                   <span className="transition group-hover:-translate-x-1">←</span>
                 </button>
                 <p className="mt-3 text-xs text-white/40">
-                می‌توانید همین حالا نسخهٔ آزمایشی را ببینید
+                  این دکمه فقط در نسخهٔ محلی نمایش داده می‌شود
                 </p>
               </div>
+            )}
           </motion.div>
         </motion.div>
       )}