Fix directory link handling in markdown

[KJ7LNW]

Context

When clicking on directory links in markdown like [some/directory/](some/directory/), the application does not know how to open the link in the explorer tree. Gemini 2.5 references directory sometimes, so this feature makes it possible to click on those links.

Clicking test/ takes you here:

Implementation

Enhanced the openFile function to better handle directory links in markdown:

• Added support for resolving ./SimpleName paths to home directory if not found in workspace
• Improved path resolution by checking multiple potential locations
• Ensured directories are properly revealed in the Explorer view
• Added attempt to expand directories after revealing them

How to Test

1. Create a markdown link to a directory outside your workspace, e.g., [Desktop](Desktop)
2. Click on the link
3. Verify the directory is revealed in the Explorer view

Fixes #3686

---

Important

Enhance openFile in open-file.ts to handle directory links in markdown by resolving paths to home directory, checking multiple locations, and revealing directories in Explorer.

• Behavior:
  • Enhanced openFile function in open-file.ts to handle directory links in markdown.
  • Resolves ./SimpleName paths to home directory if not found in workspace.
  • Checks multiple potential locations for path resolution.
  • Reveals directories in Explorer view and attempts to expand them.
• Error Handling:
  • Throws error if path does not exist and creation is not allowed.
  • Logs warning if directory expansion fails.
• Misc:
  • Keeps original file path for error messages.
  • Minor refactoring for clarity and efficiency.

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[daniel-lxs]

This looks goods to me, just a minor point that might be worth paying atenttion.
It makes sense to also handle directory paths when the model links them.

[daniel-lxs]

Hey @KJ7LNW Would it be a good idea to prevent directory traversal?
Something like this could work:

if (relativePart.includes('..')) {
    throw new Error('Path contains directory traversal pattern');
}

Or maybe something more sophisticated would make sense.

I just tested your implementation and I see some weird behavior when the model outputs a path like ..

[KJ7LNW]

Did the directory that it referenced using ../ exist, or was it just missing?

Can you provide a specific example so I can understand better?

I think we need to expect the model will sometimes render things in a way that is not expected; worst case the link is broken, but I do not think that is a problem.

Render-output handling is always best effort: the models are pretty good, but you never know what you are going to get.

[daniel-lxs]

Here's how it behaves for me, it's probably a non-issue though, that's why I left this PR for review.

2025-05-29.17-17-13.mp4

Apologies for the awful quality.

[KJ7LNW]

that is strange behavior. if anything, .. should mean ${workspace}/.. but you're right, non-issue no one will need to click on ".."