Fix invalid wam package imports

[kkchandi]

Summary

• replace invalid wam imports with the installed wham package
• import SNIPPETS_DIR from codatools, matching the existing fine-tuning script

Why

setup.py installs the package as wham and the repository contains no wam module, so the affected scripts otherwise fail during import.

Validation

• compiled the affected Python source with python -m compileall
• imported the referenced wham constants and utility functions