fix: multi-subscription frontend improvements

- Connection page: reads subscription_id from ?sub= query param
- Subscription detail: passes subscriptionId to /connection URL
- Dashboard: skip single-subscription and devices queries in multi-tariff
  mode (data comes from subscriptions-list instead)

src/pages/Subscription.tsx

@@ -794,7 +794,7 @@ export default function Subscription() {
                       haptic.notification('error');
                       return;
                     }
-                    navigate('/connection');
+                    navigate(subscriptionId ? `/connection?sub=${subscriptionId}` : '/connection');
                   }}
                   className={`mb-5 flex w-full items-center gap-3.5 rounded-[14px] p-3.5 text-left transition-shadow duration-300${isAtDeviceLimit ? 'cursor-not-allowed opacity-50' : ''}`}
                   style={{ fontFamily: 'inherit' }}