v1 bug: desktop restart behavior should be more observable after account switch

[Nirandre]

Background

Account switching depends on fully shutting down Codex Desktop, restoring the target account snapshot, and relaunching the desktop app.

During development, there were cases where the UI reported that switching was complete even though the desktop process had not obviously restarted from the user’s perspective.

Goal

Make desktop restart behavior observable and trustworthy.

Expected behavior

• The manager should only report success after the previous desktop process tree is gone and a new desktop process tree has started.
• The UI should expose clearer progress states such as:
  • shutting down desktop
  • restoring account snapshot
  • relaunching desktop
  • waiting for target account to become active
• Failures should be shown as actionable errors instead of silent hangs or ambiguous success messages.

Notes

This is mainly a UX and observability improvement around an already working v1 switch flow.