[BUG] Markdown file links in VS Code extension not clickable on macOS

Description

Markdown file links in Claude Code VS Code extension chat responses are clickable (appear as blue hyperlinks) but nothing happens when clicked. This is similar to #10846 but occurring on macOS.

Environment

• Platform: macOS (darwin)
• OS Version: Darwin 25.1.0
• Claude Code version: 2.0.76
• VS Code: Latest stable
• Extension mode: Webview (not terminal mode)

Steps to Reproduce

1. Open a workspace in VS Code with Claude Code extension
2. Ask Claude to reference a file in a response
3. Claude responds with markdown link like [file.md](path/to/file.md)
4. Click the link
5. Nothing happens

Expected Behavior

Clicking the link should open the file in VS Code editor.

Actual Behavior

Link appears clickable (blue, underlined on hover) but clicking produces no action.

Observations

• The "Read [file]" and "Edit [file]" action buttons in Claude's thinking section work correctly
• The same markdown syntax works fine in regular .md files previewed in VS Code
• Tried both relative paths and full paths from workspace root - same result
• Issue persists across VS Code restarts

Workarounds

• Using Cmd+P (Quick Open) and pasting file paths
• Clicking action buttons instead of markdown links
• Using terminal mode (untested if this fixes the issue)

Related Issues

• #10846 - Same symptoms but tagged as Windows-only

Additional Context

This appears to be an issue with how the webview handles vscode.open command URIs for file paths, not a VS Code configuration issue.