fix: clarify requirements

A requirement like >=6.33.2 includes >=7.0.0. This was not the intention.
Clarify by limiting upper versions to original intention.

Also declare script dependencies for versions, making them runnable outside the 
context of this repository, and removing pillow as a dev dependency for the 
project. To run the examples with a locally edited version of wlsonar, we can
do: 

    uv run --with-editable . examples/convert_recording.py