feat: add subscription reissue button with cooldown timer

- Add revokeSubscription API method
- Add reissue button in Additional Options with amber styling,
  destructive confirm dialog, 15-min cooldown with countdown timer,
  localStorage persistence across page reloads
- Add i18n keys in all 4 locales (en, ru, zh, fa)

src/pages/Subscription.tsx

@@ -202,6 +202,9 @@ export default function Subscription() {
 
   // Traffic refresh state
   const [trafficRefreshCooldown, setTrafficRefreshCooldown] = useState(0);
+
+  // Revoke (reissue) cooldown state
+  const [revokeCooldown, setRevokeCooldown] = useState(0);
   const [trafficData, setTrafficData] = useState<{
     traffic_used_gb: number;
     traffic_used_percent: number;
@@ -464,6 +467,41 @@ export default function Subscription() {
     return () => clearInterval(timer);
   }, [trafficRefreshCooldown]);
 
+  // Initialize revoke cooldown from localStorage on mount
+  useEffect(() => {
+    const ts = localStorage.getItem(`revoke_ts_${subscriptionId ?? 'default'}`);
+    if (ts) {
+      const elapsed = Math.floor((Date.now() - parseInt(ts, 10)) / 1000);
+      const remaining = Math.max(0, 900 - elapsed);
+      setRevokeCooldown(remaining);
+    }
+  }, [subscriptionId]);
+
+  // Countdown timer for revoke cooldown
+  useEffect(() => {
+    if (revokeCooldown <= 0) return;
+    const timer = setInterval(() => {
+      setRevokeCooldown((prev) => Math.max(0, prev - 1));
+    }, 1000);
+    return () => clearInterval(timer);
+  }, [revokeCooldown]);
+
+  // Revoke (reissue) subscription mutation
+  const revokeMutation = useMutation({
+    mutationFn: () => subscriptionApi.revokeSubscription(subscriptionId),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['subscription'] });
+      queryClient.invalidateQueries({ queryKey: ['connection-link', subscriptionId] });
+      queryClient.invalidateQueries({ queryKey: ['subscriptions-list'] });
+      haptic.notification('success');
+      localStorage.setItem(`revoke_ts_${subscriptionId ?? 'default'}`, Date.now().toString());
+      setRevokeCooldown(900);
+    },
+    onError: () => {
+      haptic.notification('error');
+    },
+  });
+
   // Auto-refresh traffic on mount (with 30s caching)
   useEffect(() => {
     if (!subscription) return;
@@ -494,6 +532,16 @@ export default function Subscription() {
     }
   };
 
+  const handleRevoke = async () => {
+    const confirmed = await destructiveConfirm(
+      t('subscription.revoke.warning'),
+      t('subscription.revoke.confirmBtn'),
+      t('subscription.revoke.title'),
+    );
+    if (!confirmed) return;
+    revokeMutation.mutate();
+  };
+
   // In multi-tariff mode without a specific subscription ID, redirect to list
   if (isMultiTariff && !subscriptionId && !isLoading) {
     return <Navigate to="/subscriptions" replace />;
@@ -2244,6 +2292,53 @@ export default function Subscription() {
                 )}
               </div>
             )}
+
+            {/* Reissue Subscription */}
+            <div className="mt-4">
+              <button
+                onClick={handleRevoke}
+                disabled={revokeMutation.isPending || revokeCooldown > 0}
+                className="w-full rounded-xl border border-amber-500/30 bg-amber-500/10 p-4 text-left transition-colors hover:bg-amber-500/20 disabled:opacity-50"
+              >
+                <div className="flex items-center justify-between">
+                  <div>
+                    <div className="font-medium text-amber-400">
+                      {t('subscription.revoke.button')}
+                    </div>
+                    <div className="mt-1 text-sm text-dark-400">
+                      {revokeCooldown > 0
+                        ? t('subscription.revoke.cooldown', {
+                            minutes: Math.floor(revokeCooldown / 60),
+                            seconds: revokeCooldown % 60,
+                          })
+                        : t('subscription.revoke.description')}
+                    </div>
+                  </div>
+                  <div className="text-amber-400">
+                    {revokeMutation.isPending ? (
+                      <div className="h-5 w-5 animate-spin rounded-full border-2 border-amber-400/30 border-t-amber-400" />
+                    ) : (
+                      <svg
+                        className="h-5 w-5"
+                        fill="none"
+                        viewBox="0 0 24 24"
+                        stroke="currentColor"
+                        strokeWidth={1.5}
+                      >
+                        <path
+                          strokeLinecap="round"
+                          strokeLinejoin="round"
+                          d="M16.023 9.348h4.992v-.001M2.985 19.644v-4.992m0 0h4.992m-4.993 0 3.181 3.183a8.25 8.25 0 0 0 13.803-3.7M4.031 9.865a8.25 8.25 0 0 1 13.803-3.7l3.181 3.182"
+                        />
+                      </svg>
+                    )}
+                  </div>
+                </div>
+              </button>
+              {revokeMutation.error && (
+                <p className="mt-2 text-sm text-red-400">{getErrorMessage(revokeMutation.error)}</p>
+              )}
+            </div>
           </div>
         )}