docs update

Create settings.local.json

Streamline README, move detailed API docs to API_GUIDE.md

Update README with .tgz performance recommendations and Arrow Table types

Fix .tgz support for scanner data and mixed data directories

Fix expected column sets and read_year bug from panel data testing

Modernize kiltsreader: PyArrow 17+, .tgz support, Arrow-native data, format resilience

Reapply "Update module.py"

Revert "Update module.py"

Update module.py

reduce memory usage of agg_fun

fixed aux_write_direct

fixed parquet write for pyarrow tables in PanelReader

dept filter bug

department filtering