* Add a path test suite

* Demonstrate the bug

* Break everything

* Refactors CutPrefix tests for clarity

Reorders arguments in CutPrefix test table to improve readability and make the tests easier to understand.

* wip

* Fixes rooted path handling in mapped filesystem

Normalizes path handling within the mapped filesystem to correctly process rooted paths.

The previous implementation had issues with absolute paths, particularly in `CutPrefix`, which led to incorrect file lookups and unexpected behavior when opening or writing files with absolute paths.

This change ensures that rooted paths are correctly handled, allowing the filesystem to function as expected with both relative and absolute paths.