Can't reference files from other directories added later

### Describe the bug

- I start a copilot session in folder `X`
- Now i can add files to the prompt with `@somefile`
- Now I use `/add-dir Y`
- If I use `@...` to add more files then I can't select files from `Y` (nothing is found)

### Affected version

Version 0.0.358 · Commit f5a8b1e76

### Steps to reproduce the behavior

_No response_

### Expected behavior

When I add more folders I can add them to the prompt like with the inital folders files.

### Additional context

_No response_