Codex Desktop on macOS fails to open chat file links in the built-in preview

What version of the Codex App are you using?

ChatGPT Desktop 26.707.72221 (5307), bundled Codex CLI 0.144.2.

What subscription do you have?

Not relevant to this local file preview issue.

What platform is your computer?

macOS 26.5 (Build 25F71), Apple Silicon arm64.

What issue are you seeing?

Clickable workspace file links in assistant messages cannot be opened correctly in the built-in file preview.

Two link forms fail differently:

1. A file link without a line number, such as [Foo.php](/Users/me/project/src/Foo.php), navigates to the containing project directory instead of opening the file.
2. A file link with a line number, such as [Foo.php](/Users/me/project/src/Foo.php:198), opens the right-side built-in file preview, but the preview displays "Unable to open file" and the app shows an error toast.

The target files exist, are readable, and appear in the workspace file tree. Opening the same files directly through the configured external editor works, so this appears to be an internal file-link routing or preview-loading issue rather than an editor integration problem.

This was reproduced with several PHP files in the same local workspace.

Steps to reproduce

1. Open a local Git workspace in ChatGPT Desktop on macOS.
2. Have Codex return a Markdown link to an existing workspace file:

• [Foo.php](/absolute/path/to/project/src/Foo.php)
• [Foo.php](/absolute/path/to/project/src/Foo.php:198)

1. Click the link without the line number.
2. Observe that the app navigates to the directory instead of opening the file.
3. Click the link with the line number.
4. Observe that the built-in right-side preview opens but reports "Unable to open file".

What is the expected behavior?

Both links should open the existing file in the built-in file viewer. When a line number is provided, the viewer should focus or reveal that line.

Additional information

This is related to #25652 because both concern workspace file links opening in the built-in viewer. However, the behavior here is different: the built-in viewer itself fails to load the file, while the link without a line number is treated like a directory navigation target.

The issue does not appear to depend on PhpStorm or any other external editor.