feat(pairing): auto-close the QR/link dialog once the device connects

The pairing session is single-use, so it leaving the pending list (polled
every 5s) means it was redeemed — close the dialog and toast success. Armed
only after the pairing has been seen in the pending list, so the stale list
at result-phase open can't blink the dialog shut; expired/cancelled sessions
close it silently. Pending-list polling now preserves the previous list on a
transient fetch failure instead of blanking it (which would also have faked
the redeem signal).

packages/ui/src/lib/i18n/messages/uk.settings.ts

@@ -263,6 +263,7 @@ export const settingsDict = {
   "settings.remoteInstances.clientAuth.addDevice.fallback.preferLocal": "Віддавати перевагу прямому домашньому підключенню, коли доступне",
   "settings.remoteInstances.clientAuth.addDevice.create": "Створити QR-код",
   "settings.remoteInstances.clientAuth.addDevice.done": "Готово",
+  "settings.remoteInstances.clientAuth.addDevice.connectedToast": "Пристрій підключено.",
   "settings.remoteInstances.clientAuth.pairingUrl": "Посилання для підключення",
   "settings.remoteInstances.clientAuth.createdToken": "Скопіюйте цей токен зараз. З міркувань безпеки він більше не показуватиметься.",
   "settings.remoteInstances.clientAuth.state.loading": "Завантаження токенів...",