First-run setup no longer gets falsely stuck at the restart step

Highlights

• · The root cause of the 'setup is stuck asking me to restart' problem is fixed. Harmless background file-cleanup that Windows does on its own was being mistaken for 'a restart is required', so first-run setup would stop and demand a restart that nothing actually needed, and could get stuck there. Setup now correctly ignores that harmless noise and keeps going. When a restart genuinely is needed, it still asks for one - that side was carefully checked too, so the change does not skip real restarts.
• · This one was tested the whole way through, not just in theory: a clean first install, an install on a machine that really did have a Windows restart pending, and the case where you choose to skip the restart and continue. All three behave correctly now.
• · One rough edge we are still chasing, so you know what to expect: in one specific situation the step right after a restart can sit with no progress shown for a few minutes before it continues. It is working, not frozen, but it looks like nothing is happening. If a setup seems to pause there, give it a few minutes; if it truly never continues, please send a diagnostic report so we can pin down the last of it.