room SCROLL applet: live async refresh over WebSocket (not just on page reload)

The room's scroll-of-events feed only updated on refresh — a gamer
watching the SCROLL view never saw a co-player's deposit / role pick /
sig appear. Now every recorded GameEvent nudges all open room sockets to
re-fetch the feed.

- drama.models.record() broadcasts a `scroll_update` to the `room_<id>`
  group via transaction.on_commit — so the live re-fetch sees the
  committed row, and a rolled-back TestCase never fires it (zero overhead
  / channel-layer traffic for the plain IT suite). _broadcast_scroll_update
  is fully guarded: a missing/unreachable channel layer must NEVER break
  event recording (falls back to refresh-to-update). One central hook
  covers every event writer, current + future.
- RoomConsumer gains a `scroll_update` relay handler (same one-liner shape
  as gate_update / turn_changed).
- New `scroll_status` view + url (epic:scroll_status,
  room/<id>/scroll/status) renders JUST core/_partials/_scroll.html with
  the same events/viewer/scroll_position context as room_view's inline
  paint, so the swapped feed is identical.
- room-scroll.js listens for `room:scroll_update`, fetches the partial,
  swaps #id_drama_scroll, then re-applies the saved Frame/Redact filter +
  restarts the buffer dots on the fresh nodes. URL comes from
  .room-page[data-scroll-status-url]. Refactored the dots + filter into
  re-runnable helpers; existing behavior (title reel IO, filter form,
  localStorage) preserved.

TDD:
- drama RecordBroadcast ITs: record() schedules the broadcast on commit
  (captureOnCommitCallbacks execute=True) and NOT before commit.
- RoomConsumer relays scroll_update (InMemory layer, WebsocketCommunicator).
- ScrollStatusViewTest: endpoint renders the feed section, reflects the
  latest events, is the bare partial (no navbar/aperture chrome).
544 drama+epic ITs green — the on_commit hook is inert under TestCase, so
no existing event-writer test regressed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/apps/drama/models.py

@@ -214,9 +214,34 @@ class ScrollPosition(models.Model):
         return f"{self.user.email} @ {self.room.name}: {self.position}px"
 
 
+def _broadcast_scroll_update(room_id):
+    """Nudge every open room socket to re-fetch the scroll-of-events feed so the
+    SCROLL applet updates live (not just on page refresh). Guarded — a missing
+    or unreachable channel layer must NEVER break event recording, so any error
+    is swallowed (the feed simply falls back to refresh-to-update)."""
+    try:
+        from asgiref.sync import async_to_sync
+        from channels.layers import get_channel_layer
+        layer = get_channel_layer()
+        if layer is None:
+            return
+        async_to_sync(layer.group_send)(
+            f"room_{room_id}", {"type": "scroll_update"})
+    except Exception:
+        pass
+
+
 def record(room, verb, actor=None, **data):
-    """Record a game event in the drama log."""
-    return GameEvent.objects.create(room=room, actor=actor, verb=verb, data=data)
+    """Record a game event in the drama log.
+
+    Broadcasts a `scroll_update` to the room group AFTER the surrounding
+    transaction commits (`on_commit`) so the live re-fetch sees the new row,
+    and so a rolled-back TestCase never fires it (zero overhead/risk for the
+    plain IT suite). RoomConsumer relays it → room-scroll.js swaps the feed."""
+    from django.db import transaction
+    event = GameEvent.objects.create(room=room, actor=actor, verb=verb, data=data)
+    transaction.on_commit(lambda: _broadcast_scroll_update(room.id))
+    return event
 
 
 _NOTE_DISPLAY = {