Add note on Copilot sign out/in to troubleshooting page (#255)

* Add note on Copilot sign out/in to troubleshooting page

* Linting

* Remove outdated callout about remote SSH + Copilot

* Update assistant-troubleshooting.qmd

Co-authored-by: sharon <sharon-wang@users.noreply.github.com>

---------

Co-authored-by: sharon <sharon-wang@users.noreply.github.com>

Author: juliasilge

assistant-getting-started.qmd

@@ -105,10 +105,6 @@ Students and faculty can use GitHub Copilot for free as part of the GitHub Educa
 1. Click the **Sign in** button to initiate GitHub's OAuth authentication flow.
     - Complete the authentication flow in your browser, and return to Positron when finished.
 
-::: {.callout-tip}
-If you are using Positron with a [remote SSH](remote-ssh.qmd) session, you will need to authenticate to GitHub on the _remote server_ as well. Follow [along on GitHub](https://github.com/posit-dev/positron/issues/8409) as we make improvements in this area.
-:::
-
 ## Amazon Bedrock
 
 ::: {.callout-important}

assistant-troubleshooting.qmd

@@ -7,6 +7,14 @@ If you're having trouble with Positron Assistant, here are some resources and to
 
 Can't find what you're looking for? Reach out through our [feedback channels](#feedback-issues) and we'll help you out!
 
+::: {.callout-important}
+## GitHub Copilot authentication change
+
+In Positron 2026.01.0, Positron Assistant has switched to using a native implementation of the Copilot completion engine, addressing a variety of authentication and performance issues. Copilot credentials now also work in Remote SSH sessions, and VS Code proxy settings are respected when connecting to GitHub Copilot. 
+
+However, if you were logged in to GitHub Copilot previously, you will need to **sign out and back in** to use Copilot in this latest release. See this [discussion post](https://github.com/posit-dev/positron/discussions/11340) for more information.
+:::
+
 ## I am getting unexpected or incorrect responses
 
 If you receive unexpected or incorrect responses from Assistant, consider the following steps: