[BUG] VSCode Extension import failure within CLAUDE.md for adjacent AGENTS.md file

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

When using the `@path` import feature in `CLAUDE.md` to import an adjacent (same folder) `AGENTS.md` file, the import fails from within the VSCode extension, but works in the terminal. I have had Claude Code investigate and test this itself, checking it's context both on the terminal and within VSCode and it recommended I file a bug report, as the import fails and it sees the `@AGENTS.md` text verbatim via the VSCode extension context and the fully expanded text via the terminal.

**[EDIT]** Note, I have checked this on a colleague's Mac and the bug does not exist there, it is purely a problem on the Windows version of the Claude for VSCode plugin, and has been for some time. The bug is with the `@import` feature, possibly permissions based?

### What Should Happen?

The `@path` import command should work correctly from within the VSCode extension in an identical fashion to how it works anywhere else.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

1. Create a CLAUDE.md file and add an import of AGENTS.md to it.
2. Create AGENTS.md with actual context instructions in it.
3. Open a session within VSCode extension and see if it reads the context from AGENTS.md, repeat in a terminal to see the difference

### Claude Model

Not sure / Multiple models

### Is this a regression?

I don't know

### Last Working Version

_No response_

### Claude Code Version

2.1.220 (Claude Code)

### Platform

Anthropic API

### Operating System

Windows

### Terminal/Shell

VS Code integrated terminal

### Additional Information

There are similar tickets for this in the past, but they have been closed due to inactivity and locked and this is still a persistent serious bug. The previous issue that is similar #13983 was marked as a duplicate of other issues that were not VSCode specific and didn't mention VSCode, it only effects the extension, possibly why other tickets did not amount to a fix.

Start by reproducing the adjacent AGENTS.md import with CLAUDE.md on Windows in the VS Code extension, then compare the same files and import from a terminal session. The work is done when @AGENTS.md is expanded identically in both contexts; no failing test or implementation file is identified in the report.

Written by the indexing model from the issue text.