"Failed to start session" for repos behind SSO when authenticated with the SSO

### Short summary

Cloud sessions consistently fail with "Failed to start session" for repos behind SSO

### Affected version or release

v1.0.23

### Installation context

macOS

### What happened?

Cloud sessions consistently fail with "Failed to start session" for repos behind SSO when authenticated with the SSO, but cloud sessions work for personal repos.

I have double checked if I am authenticated with the SSO by logging out, and logging out in browser too, then logging in in the app, logging into GitHub, authenticating the SSO, then approving the apps access.

Cloud sessions work perfectly in personal repos without any issues.

Cloud sessions started from github.com also work perfectly find with the SSO repo too. It's just cloud sessions started from the desktop app that fail with the SSO repo.

### Steps to reproduce

1. Start a new session on a repo that is behind SSO
2. Choose "Cloud"
3. Start session with a prompt
4. See "Failed to start cloud session"
5. See it continue to use the local agent instead

### Expected behavior

Cloud sessions should work for SSO repos.

### Additional context

_No response_

No source file, test, or entry point is named in the report. Start by reproducing the failure from the macOS desktop app with an SSO-protected repository, comparing it with a personal repository and a session started from github.com; done means desktop-started cloud sessions work for SSO repositories without falling back to the local agent.

索引モデルが issue の本文から書いたものです。