The module docstrings and the notepad still described one rebuild that
touches everything. Closes the toggle cost, the seeding cost, the
per-save rebuild, the modules/apply rebuild and the Playwright spec that
could not fit a rebuild into its five seconds; files the follow-ups the
refactor leaves behind.
A wheel whose top-level module is `app` collides with anything else in a
user's venv, so the package that is about to be published takes the name
it is published under. Only the Python package moves; the repo, the
Docker WORKDIR and the compose project keep theirs.