refactor: decouple GO enrichment logic and improve data flow safety (#10)

* test commit

* feat: temporal commit

* feat: integrate GO term analysis into execution method

* refactor: extract GO enrichment analysis into a separate method

* refactor: pass results_dir to _run_go_enrichment to handle output paths

* fix: remove incorrect reassignment of results_dir to input-files

* feat: upgrade statistical analysis from p-value to p-adj (FDR)

Author: hjn0415a