Script pane, realtime peer sync, and logout button

- Script pane: PDF tab beside annotations; "Add script annotation" arms
  highlight mode on the draft, ✓/✕ to confirm/cancel, auto-scrolls to the
  active annotation's highlights during playback. Adds Project.script.
- Realtime: Django Channels websocket per project broadcasts attributed
  scene deltas after each save; peers merge them in (keeping local drafts).
- Logout link in the editor project-bar.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scenes/views.py

@@ -1,5 +1,7 @@
 import json
 
+from asgiref.sync import async_to_sync
+from channels.layers import get_channel_layer
 from django.contrib.auth import authenticate, login as dj_login, logout as dj_logout
 from django.db import transaction
 from django.db.models import Q
@@ -53,6 +55,7 @@ def _meta(request, project):
         "owner": project.owner.get_username(),
         "otio": request.build_absolute_uri(project.otio.url) if project.otio else None,
         "clip": request.build_absolute_uri(project.clip.url) if project.clip else None,
+        "script": request.build_absolute_uri(project.script.url) if project.script else None,
         "thumbnail_status": project.thumbnail_status,
         "thumbnail_error": project.thumbnail_error,
         "thumbnails": thumbnails or None,
@@ -150,6 +153,15 @@ def scene(request, pk):
             if any(counts.values()):       # don't log a no-op save
                 Revision.objects.create(project=p, user=request.user, summary=summary,
                                         annotations=annotation_layer(p.scene))
+                # push the attributed delta to peers viewing this project
+                scene_groups = (p.scene or {}).get("groups", {})
+                async_to_sync(get_channel_layer().group_send)(
+                    f"project_{p.pk}",
+                    {"type": "scene.delta",
+                     "delta": {"changed": {gid: scene_groups[gid]
+                                           for gid in changed if gid in scene_groups},
+                               "deleted": list(deleted),
+                               "by": request.user.get_username()}})
         if "fps" in data:
             p.fps = data["fps"]
         p.save(update_fields=["scene", "fps", "updated"])