v0.3.1

Changes since v0.3.0:

• 0.3.1
• docs: CHANGELOG 0.3.1 dated
• web: the shell cache test stands in its own index.html, so it passes on a tree vite has not built
• tasks, core: the seed heading names what it shows and hides; the stop rule's deletion is scoped to what the run did not create
• tasks, core: a run decides reversible choices itself and reports in two parts; the seed lists only runs that still need the head

pier update stops the service and writes a copy of the database to
~/.pier/db/backups/ before installing. Schema migrations are one-way.
See docs/deploy.md.