fix: DEP0169

[sjinks]

This PR fixes the Passing invalid argument types to fs.existsSync is deprecated warning.

[Copilot]

Pull Request Overview

This PR addresses the deprecation warning triggered by calling fs.existsSync with non-string arguments by adding explicit type checks before invoking fs.existsSync.

• Add typeof ... === 'string' guards before fs.existsSync calls in various filter chains in lib/lando.js.
• Refactor the exports.loadFiles filter in lib/config.js to safely handle both string sources and objects with a file property.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
lib/lando.js	Added string-type checks before calling fs.existsSync in multiple filter steps
lib/config.js	Replaced simple fs.existsSync calls with a branch that validates source and source.file types

Comments suppressed due to low confidence (1)

lib/config.js:196

• Consider adding unit tests for loadFiles to cover cases where inputs are non-strings or objects without a file property to ensure the filter logic behaves as expected.

    .filter(source => {