Reference CLAUDE.md and PLAN.md for full context before doing anything.

Task: Clean up the repository before packaging. This is a hygiene pass,
no new logic.

- Remove scratch/debug artifacts from the repo root that accumulated
  during development (e.g. debug.py, scratch.py, test_typer.py if it's a
  stray manual-testing file rather than part of the real tests/ suite,
  and any tmp*_prepared.csv / tmp*_pipeline.joblib / tmp*_report.json
  files left over from manual CLI runs).
- Update .gitignore (from Phase 0) to explicitly exclude: tmp*, *.joblib,
  scratch.py, debug.py, and any other pattern matching leftover manual-
  test artifacts, so this doesn't recur.
- Move tests/integration/ and tests/edge_cases/ (from Phases 10-11) into
  the pytest configuration's awareness if not already — confirm
  pyproject.toml's [tool.pytest.ini_options] testpaths includes tests/
  recursively and the "integration" marker (registered in Phase 10.1) is
  still correctly configured.
- Verify README.md (stub from Phase 0) — do not fully rewrite it yet
  (that's part of 12.2), but confirm it isn't referencing anything now
  stale (e.g. placeholder text that says "coming soon" for features that
  are now built).
- Run the full test suite (`pytest tests/ -m "not integration"` for fast
  unit tests, then `pytest tests/ -m integration` separately) and confirm
  everything passes cleanly on a fresh clone/install after cleanup —
  this catches any accidental breakage from deleting files.

After cleanup, update CLAUDE.md's "Current focus": note packaging in
progress, 2 of 3 sub-steps remaining (pyproject.toml metadata, coverage). also update the plan.md with relavant entries under "Architecture decisions log" and "Implementation order" sections. 






 also update the plan.md with relavant entries under "Architecture decisions log" and "Implementation order" sections. 