feat: add stop option to detect

[luxass]

Description

This PR adds a new stop option to detect and detectSync. This will allow us to stop traversing directories when a certain directory is hit.

Linked Issues

N/A

Additional context

N/A

[benmccann]

What is the motivation for this?

[luxass]

What is the motivation for this?

I needed this feature for testing package manager detection in my codebase that uses pnpm. Specifically, I have tests that should return null when no package manager is found, but without the stop option, the traversal continues upward and finds the pnpm configuration at the repository root, causing the test to fail. The stop option allows me to properly test these scenarios by limiting how far up the directory tree the search goes.