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>

server/settings.py

@@ -32,6 +32,9 @@ CSRF_TRUSTED_ORIGINS = [
 ]
 
 INSTALLED_APPS = [
+    # First, so `runserver` is daphne's and serves the websocket too.
+    "daphne",
+    "channels",
     "django.contrib.admin",
     "django.contrib.auth",
     "django.contrib.contenttypes",
@@ -51,6 +54,10 @@ MIDDLEWARE = [
     "django.contrib.messages.middleware.MessageMiddleware",
 ]
 
+# Process-local, like the consumer's ROOMS: one worker. docs/architecture.md
+# names the move — Redis — for the day there is a second.
+CHANNEL_LAYERS = {"default": {"BACKEND": "channels.layers.InMemoryChannelLayer"}}
+
 ROOT_URLCONF = "server.urls"
 WSGI_APPLICATION = "server.wsgi.application"
 ASGI_APPLICATION = "server.asgi.application"