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>

clips/migrations/0009_revision_blocks.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2.17 on 2026-09-30 01:54
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('clips', '0008_owners_editors_leaf_seq'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='revision',
+            name='blocks',
+            field=models.JSONField(default=dict, help_text="each clip's tier-2 block keys, by cid, so a restore can name them"),
+        ),
+    ]