fix: pathsToSave should allow saving parent paths of whitelisted paths

[Bitshifter-9]

This PR fixes an issue where pathsToSave would skip updates when a modified path was a parent of one of the whitelisted paths. As a result, valid updates were being ignored even though they should have been saved.

What Was Changed

In lib/model.js, the save method now checks whether the modified key is either:

a parent of a whitelisted path, or

a child of it.

If either condition matches, the path is correctly included in the delta.

Verification

Added a dedicated test file test/gh-paths-to-save.test.js to reproduce the issue and validate the fix.

Ran all existing tests (test/model.test.js) to confirm no regressions.

Verified that the new test passes:

gh-paths-to-save
✔ should allow saving parent paths of whitelisted paths (gh-issue)

This ensures that parent paths are now properly saved when related whitelisted paths are updated.