76e42cbc

By: Michael Lynch <git@mtlynch.io>

Render section actions on the server

Replace imperative section-page JavaScript with HTMX forms backed by
server-side adjacent moves and rename edit fragments. Each action returns
a complete section-list replacement, including boundary-disabled controls.

Validation: ./dev-scripts/run-go-tests
Validation: ./dev-scripts/build-all-flake-targets