Cannot select source file to include in chat window via 📎 file list button when the build is out of source

**Describe the bug**
Our project is configured to have the build directory out of the source directory.
And the xcode project is generate by cmake.
The tree is like that :
```
project_src
project_build
project.xcodeproj
bin
etc ...
```
In this configuration copilot don't list file from the source directory.
It only list file from the build directory.

**Versions**
- Copilot for Xcode: [e.g. 0.32.0]
- Xcode: [e.g. 16.2]
- macOS: [e.g. 15.3.2]

**Steps to reproduce**
clic on 📎 and only files inside the project_build appear.

**Screenshots**

**Logs**
No error in the log file

**Additional context**