Address [[ https://linear.app/comm/issue/ENG-10822/web-loading-indicator-after-qr-auth | ENG-10822 ]]. Added a UI component to track restoration. Video in the comment.
This UI:
- Enabled only when `fullBackupSupport` is true
- Step 1. Tracks QR auth progress (starting when received first message from primary device)
- Step 2. Restoration progress
- Step 3. Complete is actually never shown, user is immediately redirected to the app UI
- Error modal shown in the video is not covered by this diff.
The UI was generated by Claude, with some manual refactors.
Depends on D14919, D14914