Setup recovers from the stuck restart step, and sign-in tells the truth

Highlights

• · First-run setup could get stuck in a loop at the Windows restart step - you'd click Restart and it would never finish. This release makes it recover: SpawnBox now correctly detects when the restart actually happened and continues instead of looping. This was one of the biggest things blocking new installs. If you still hit a setup that stalls, please send a diagnostic report so we can chase the rest.
• · If your sign-in actually expired, SpawnBox used to keep looking signed-in while quietly failing to sync in the background - sometimes for days before you noticed. It now shows a clear 'Sign back in' button the moment that happens, so nothing fails silently anymore.
• · Signing in is calmer. Instead of briefly flashing a 'signed out' look right after you sign in, you now get a short 'Signing in...' spinner while things settle. If you still see a stuck signed-out state after a successful sign-in, let us know - we want to confirm this one is fully closed.
• · The first-run setup wizard no longer freezes on a stuck message for about 30 seconds, and clicking past a step now responds in a few seconds instead of sometimes taking up to a minute.
• · If your sign-in briefly hiccups, SpawnBox now keeps offering you updates on the channel you chose (like beta) instead of silently dropping you back to stable.