Replaces the manual "I've installed it" button in AddMacSheet with an
auto-advancing waiting-pill. As soon as the backend flips status from
pending → active (triggered by the DoH handshake from the AdGuard
watcher), the sheet jumps to the success step automatically.
- useProtectedDevicesRealtime hook subscribes to rebreak.protected_devices
UPDATE events for the current user, with auto-reconnect on CHANNEL_ERROR
- AddMacSheet listens only while in step 2 (download/install)
- devices.tsx keeps a list-level subscription so the table refreshes even
if the user dismissed the sheet before activation
- i18n: waiting_install / waiting_hint / activated_toast (DE + EN)
