feat: update backing value for default config

[maxrzaw]

This will help with files position not being saved when you harpoon a file that is relative path from the cwd and is not a path from root and then leave the file without marking it again.

• fix unit test swap file issue
• add test for relative files
• add test for context not being saved

[maxrzaw]

This addresses one of the issues mentioned in the comments of #441. Does not address the issue of lists not being saved on quit.

[ThePrimeagen]

I'm going to try to look closer at this. I may merge this though. I worry it's going to cause issues. I don't like the two levels of translation.

[maxrzaw]

Hold off on that. I might have found a bug in the create_list_item function.

[maxrzaw]

Ok, turns out this bug already exists in the harpoon2 branch #476. This change makes it slightly different, but it still happens.

Basically the case is where I have an item in the list and I create a duplicate.
The issue I am having on this branch is that when save the UI with two items that are the same value after they are normalized, i.e ("./README.md" and "README.md"), they are both saved, which results in a duplicate in the list. On this branch they are then displayed the same the next time around which results in similar issues to #476. The problem on this branch is that two values may not be displayed the same when they are first input, but they could be the same file.

I did find another bug with the path normalization and I'll push a fix and some tests for that. Getting more familiar with Plenary.Path.

I'm going to think about how we could solve this issue, but at the moment, I am not sure how without making a large refactor.