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/epic/tests/integrated/test_views.py

@@ -3493,6 +3493,47 @@ class RoomScrollOfEventsTest(TestCase):
         self.assertNotIn("gr-word--scroll", content)
 
 
+class ScrollStatusViewTest(TestCase):
+    """`scroll_status` renders JUST the scroll-of-events feed partial — the
+    endpoint room-scroll.js re-fetches on a `scroll_update` WS nudge to refresh
+    the SCROLL applet live (no reload). Same feed the room page paints inline."""
+
+    def setUp(self):
+        self.user = User.objects.create(email="founder@test.io", username="disco")
+        self.client.force_login(self.user)
+        self.room = Room.objects.create(
+            name="Willawonky", owner=self.user,
+            gate_status=Room.OPEN, table_status=Room.ROLE_SELECT,
+        )
+        GameEvent.objects.create(
+            room=self.room, actor=self.user, verb=GameEvent.SLOT_FILLED,
+            data={"token_type": "carte", "token_display": "Carte Blanche",
+                  "slot_number": 1, "renewal_days": 7},
+        )
+        self.url = reverse("epic:scroll_status", kwargs={"room_id": self.room.id})
+
+    def test_renders_the_scroll_feed_section(self):
+        response = self.client.get(self.url)
+        self.assertEqual(response.status_code, 200)
+        self.assertContains(response, "id_drama_scroll")
+        self.assertContains(response, "drama-event")
+
+    def test_feed_reflects_latest_events(self):
+        # A freshly-recorded event shows up on the next fetch (the live-refresh
+        # contract) without re-rendering the whole room page.
+        from apps.drama.models import record
+        record(self.room, GameEvent.ROLE_SELECTED, actor=self.user, role="PC")
+        content = self.client.get(self.url).content.decode()
+        # One `.drama-event-body` per row (the bare class appears 3×/row).
+        self.assertEqual(content.count("drama-event-body"), 2)
+
+    def test_only_partial_not_full_page(self):
+        # It is the bare feed section — no room chrome (navbar / aperture).
+        content = self.client.get(self.url).content.decode()
+        self.assertNotIn("room-aperture", content)
+        self.assertNotIn("navbar", content)
+
+
 class RoomViewsCarouselTest(TestCase):
     """The scroll pane becomes a horizontal carousel of 5 views (ATLAS /
     SCROLL / POST / CHAT / PULSE — [[project-room-game-views-carousel]]).