refactor: replace glob dependency with custom glob using node:fs

[oldregime]

This PR removes the external glob dependency to reduce the package footprint, resolving issue #551.

Since Node's native fs.promises.glob has some limitations (like not following symlinked directories and inconsistent globstar pattern behavior on certain Node versions), we implement a small, robust custom directory walker in lib/glob.js that mimics the expected interface.

Changes:

1. Implemented a zero-dependency recursive directory walker in lib/glob.js with support for globIgnore pattern-matching, dotfiles, and symlinks.
2. Updated index.js to require ./lib/glob instead of glob and removed the dependency from package.json.
3. Updated the proxyquire mock in the tests to stub ./lib/glob instead of glob, and added additional test cases to cover the callback/promise patterns and error cases of the custom glob utility to achieve 100% code coverage.

[Fdawgs]

Duplicate of #571