Replacing the current Hugging Face repository

We rebuilt ChatterjeeLab/CIS6270 from the final lecture notes, and everything in this tree is new except the four files listed under "keep" below.

Keep from the current repository

File	Why
`lecture_2/flow_unet_mnist.pt`	The published five-epoch checkpoint. `lecture_2/flow_matching_mnist.py` still defines `FlowUNet` with the same state-dict keys, so the file loads unchanged. Move it to `lecture_2/`.
`lecture_2/mnist_selected_examples.png`	The selected generations in the Lecture 2 guide.
`lecture_2/mnist_selected_trajectories.png`	The noise-to-image trajectories in the same guide.
`LICENSE`	Unchanged, MIT.

We link the overview figure at the top of the README from the Hugging Face CDN and keep no copy in the tree, so it survives the replacement on its own.

Delete

Everything else. The old tree held 67 files per lecture folder of which most were generated:

run.py, run_all.py, lecture_core.py, common.py, diffusion.py, flows.py, examples/. We replace the dispatcher with one file per framework, so you can read a method in one place.
verified_examples/ in lectures 4 to 7, about 300 JSON files, several over 200 KB. We now reproduce a seeded run by running the script, and each lecture's README lists the numbers a default run produces.
lecture_6/EQUATION_READINGS.md (138 KB) and lecture_7/lecture7_ot_sbm_notes.md (148 KB), both of which you can read in the book.
MATHEMATICS.md, SOURCES.md, SLIDE_CODE_MAP.md, source_manifest.json, paper_manifest.json, lecture7_examples.ipynb. The slide maps pointed at the decks as they were before the October rewrites.
lecture_4/data/dna_train.tsv and lecture_5/data/dna_train.tsv, which were byte-identical copies of each other. cis6270.data.synthetic_dna generates the same data in one place, and cis6270.data.write_dna_tsv writes it out in the old format for anyone who wants the file.
lecture_3/esm2_example.csv, GUIDANCE_NOTES.md, and the per-lecture requirements.txt files.

What changed for a reader

You now have a Lecture 1, covering the mathematical foundations chapter.
pip install -e . puts cis6270 on the path; otherwise we run from the repository root with PYTHONPATH=..
The shared flags are the same everywhere: --steps, --batch-size, --lr, --width, --length, --samples, --sample-steps, --seed, --device, --out, --quiet.
python -m pytest tests -q runs 484 tests, which assert the numbers the notes work by hand.