fix: directory filtering

[Nsidorenco]

No description provided.

[liskin]

This broke test discovery for me — I'm only seeing about 180 tests instead of the 910+ that are there. Any tips how to diagnose this? I tried #47 but that broke test discovery completely, it gets stuck in "Parsing tests" forever.

Reverting 9d45c1d fixes the discovery for me. (One needs to git fetch origin 9d45c1d80f4b2db1b29d65b37897e3bb71cd8d81 first because that commit got squashed into some other one for some weird reason. I'd advise against using squash merges in the future to prevent these kinds of mistakes.)

[Nsidorenco]

I inadvertently introduced a bug in the directory filtering. Sorry about that!
The problem is most likely we only look downwards for project files when filtering directories, so if the directory containing the tests are nested below the project file there is a chance it will be filtered out. (You can probably confirm this if you set neotest logging to trace and see directories it descents into)

I think #47 is on the right track so I'll focus on getting that to a point where we can merge it.