Console: "Extensions restarting..." flashes when closing, switching workspaces, etc.

System details:

Positron and OS details:

Positron Version: 2025.07.0 (Universal) build 112
Code - OSS Version: 1.100.0
Commit: d3aebd077b1b5a1ad2073966a4cc20270da68f89
Date: 2025-06-16T03:37:53.133Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0

Interpreter details:

Any

Describe the issue:

The "Extensions restarting" indicator appears in the Console in a variety of contexts that are not an extension host restart.

Steps to reproduce the issue:

1. Open Positron
2. Start an R or Python session
3. Switch to another workspace, or close Positron altogether

https://github.com/user-attachments/assets/bafe9e68-a35c-478b-9216-1d315a6565e5

Expected or desired behavior:

Console doesn't change, or indicates exiting/switching instead of restarting.

This behavior is caused by the fact that (at least as plumbed today) we only know that the extension host is exiting -- we don't know why it's exiting. It could be exiting to recover from a crash, to restart after an extension change, in preparation for exiting Positron, in preparation to switch workspaces, etc.

This flash is very brief on fast machines, but can linger for 1s or more on slower ones.

Start by reproducing the Console's "Extensions restarting..." indicator while starting an R or Python session, switching workspaces, and closing Positron. Trace the Console handling of extension-host exit events and determine how the exit context is represented. Done means the Console no longer flashes a restart message for workspace switching or application exit, while genuine restarts remain clearly indicated.