Create Ancillary Generation Pipeline image during build

# 📚 Documentation Request

## Refinement

The Ancillary Generation Pipeline page has an illustrative image in it that was generated via the diagrams package. The code for this should be lodged, the ANTS dependencies updated to allow it to be generated in there, and the running of the script integrated into the docs build process.

Locate the Ancillary Generation Pipeline documentation page and its illustrative image, then inspect how the diagrams package and ANTS dependencies are currently configured. Identify where the generation script should live and how the documentation build runs. Done means the image-generation code is lodged in the project, dependencies permit it to run, and the docs build generates the image.

Written by the indexing model from the issue text.