- Updated all GitHub Actions workflows (build-pdfs, preview-dev, publish-live, update-pdfs) to loop over `tutorial_module1` through `tutorial_module4` instead of the legacy `part1`/`part2`.
- Updated Quarto documentation (`slides.qmd`, `_quarto-html.yml`) to correctly surface the 4 new module PDFs on the website.
- Updated the tutorial Makefile to compile all 4 modules.
- Updated `.gitignore` and instructor quickstart documentation to reflect the new slide outputs.
Covers: install, first demo, first homework, semester plan, auto-grading
hints, and material inventory. Designed to minimize instructor adoption
friction for ML systems courses.