Versioned Documentation Snapshots

Policy

Living docs track the main branch (this portal).
Release snapshots (Wave 3): tag the repository (vX.Y.Z) and optionally publish a static copy of docs-site/.vitepress/dist under /versions/vX.Y.Z/ on the docs host.
Changelog entries in Changelog should reference the matching app release when domain math changes.

Use the Archive Lane for historical reports. Prefer ADR supersession notes over deleting decision history.