Documentation maintenance

Author pages in MyST Markdown. Use headings consistently, fenced code blocks with a language, relative Markdown links for pages, and toctree directives for navigation. Keep normative claims tied to the source modules and tests listed in the implementation brief.

The CLI page is generated; update command_catalog.py, Typer help, or the generator and run:

python docs/_scripts/generate_cli_reference.py
python docs/_scripts/generate_cli_reference.py --check

Add a new page to the relevant group index and keep warning-as-error builds clean. Do not hide broken references by disabling nitpicky.