can't install extension if not admin user

**Describe the bug**
The extension does not get installed if xcode/copilot are being run by a non-admin user. There's no documentation or instruction, just the extension is not there so cannot enable.

Also the UI shows when it is not enabled, but does not confirm that it is (but it does for the accessibility permission)

**Versions**
- Copilot for Xcode: 0.34.0
- Xcode: Version 16.3 (16E140)
- macOS: 15.4.1

**Steps to reproduce**
1. Install fresh with hombrew in terminal (admin user for homebrew)
2. got to settings

**Screenshots**

It would be nice if the UI could detect and confirm it sees that it is activated.

Installed by going to admin account, starting Xcode/copilot, signing into account etc.

Reproduce the fresh Homebrew installation from a non-admin user, then inspect the extension installation flow and the Settings UI described in the issue. Confirm the behavior with Xcode 16.3 and macOS 15.4.1; done means the extension is available to the non-admin user and the UI confirms whether it is enabled.

Written by the indexing model from the issue text.