Function workspace_relative_display 

pub fn workspace_relative_display(workspace_root: &Path, path: &Path) -> String

Render a path relative to the workspace when it belongs to that workspace.

Paths outside the workspace remain absolute (or otherwise unchanged) so a diagnostic never hides that it refers to an external location. The filesystem-resolved comparison handles workspace aliases and symlink escapes without requiring callers to canonicalize their candidate first.

This is the one-shot form. Loops that render many entries should build a WorkspacePathDisplay once instead, so the workspace root is canonicalized a single time rather than once per entry.