The tracker profile of the WIKIDB convention: a project's issues and
internal documents in one .tracker.mneme file at the repo root.
A tracker is an ordinary WIKIDB v3 database. Everything specific to it
lives in the manifest this module writes, so a generic viewer opens one
without knowing anything about issues. See docs/TRACKER.md.
Like wikidb, this module performs no terminal I/O: it composes text and
returns it, so the shell mode and a web view can render the same issue.