Projects live at URLs, have owners, and are edited together live

A project is only ever at /p/<id>/<slug>; / is the index of the projects
you own or edit. Every project has an owner, who can name editors;
anyone with the link can view. Every edit saves itself, one request in
flight at a time, as a patch of the leaves that changed, and a websocket
(channels + daphne) carries presence and each committed write to
everyone else in the project. The first write to a leaf wins, and the
loser is told.

Undo is per person: a step undoes only if the leaves it touched still
hold what it left, so it never takes a collaborator's work with it.
Named snapshots replace saving, and restore as an ordinary write.

An empty symbol now survives the leaf round trip with `:nodes {}`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Dockerfile

@@ -40,4 +40,4 @@ RUN python manage.py collectstatic --noinput \
 
 USER app
 EXPOSE 8000
-CMD ["sh", "-c", "python manage.py migrate --noinput && exec gunicorn server.wsgi:application --bind 0.0.0.0:8000 --workers 1 --threads 4 --timeout 120"]
+CMD ["sh", "-c", "python manage.py migrate --noinput && exec daphne --bind 0.0.0.0 --port 8000 server.asgi:application"]