fn WalkUpToProjectRoot(Start: &Path) -> PathBufExpand description
Walk up from Start looking for a project-root marker (Cargo.toml,
package.json, .git, pyproject.toml, go.mod, pnpm-workspace.yaml).
Returns the first ancestor that owns one. Falls back to Start itself
when nothing matches before the filesystem root.
Why: when a developer launches the binary from a Target/debug/ build
directory, current_dir() is the build folder, which has no source
files. vscode.workspace.findFiles('**/*') walks it and returns
nothing; the SCM panel can’t find a repo; tree-views render empty.
Walking up to the nearest project root mirrors what every
git/cargo/npm CLI does and gives extensions a workspace folder
they can actually scan.