Documentation versioning

The documentation portal tracks the code on main. Each tagged release freezes a summary under docs/versions/<major>.<minor>.md; patch releases update the same minor snapshot only for corrections. The live portal labels itself latest and links the newest frozen snapshot.

Snapshots record supported code version, commit/tag, migration baseline, API major, configuration changes, and upgrade links. They do not copy every page: Git tags are the immutable full snapshot, while the minor page is the durable entry point. Never rewrite a snapshot for behavior changes; add a new minor.

The portal uses MkDocs core with its maintained built-in theme because the repository is Markdown-first and does not need a JavaScript documentation application. Material was not selected because it is approaching end of life; Docusaurus was not selected because this portal needs no client application or large JavaScript dependency tree. Re-evaluate the theme before MkDocs 2.x. Build it with:

python -m pip install -r requirements-docs.txt
mkdocs build --strict
mkdocs serve