implement tests

it would be great to have unit tests


there was a few regressions in past few months and it would save us all time 


example how you can simulate screen in github action

https://github.com/mediar-ai/screenpipe/blob/main/.github/scripts/setup_display.sh

https://github.com/mediar-ai/screenpipe/blob/main/.github/workflows/linux-integration-test.yml