Regenerate figures, add dependency lockfile

- 3D UMAP GIF regenerated with current pipeline (5 cell types,
  2,604 cells after doublet removal). Fixes mismatch between
  README text and figures.
- Publication figure regenerated from 06_trajectory.h5ad.
- requirements-lock.txt pins all dependency versions for exact
  reproducibility (biggest gap flagged in audit).

Author: Ekin-Kahraman

README.md

@@ -110,11 +110,13 @@ Silhouette scores in single-cell data are typically low due to continuous rather
 ```bash
 git clone https://github.com/Ekin-Kahraman/single-cell-rnaseq-immune-profiling.git
 cd single-cell-rnaseq-immune-profiling
-pip install -e .
+pip install -e .                  # or: pip install -r requirements-lock.txt
 python run_pipeline.py            # full pipeline (~38s)
 python run_pipeline.py --from 6   # resume from trajectory step
 ```
 
+For exact reproducibility, use `requirements-lock.txt` which pins all dependency versions.
+
 ## Testing
 
 ```bash

docs/publication_figure.png

@@ -0,0 +1,10 @@
+anndata==0.12.10
+igraph==1.0.0
+leidenalg==0.11.0
+matplotlib==3.10.8
+numpy==2.3.5
+pandas==2.3.3
+scanpy==1.12
+scikit-learn==1.7.1
+scipy==1.16.3
+seaborn==0.13.3