fix(threads): review-wave fixes for per-thread notifications

- useRoomsListener now PREPENDS the emitting Room (was appended): the SDK emits
  RoomEvent.UnreadNotifications with VARIABLE arity (0/1/2 args), so a trailing
  extra arg landed in the wrong positional slot on the most common room-count
  sync path — room.isSpaceRoom() threw inside the SDK emit loop and the badge
  PUT never ran. Both consumers updated (CONFIRMED HIGH review finding).
- roomToUnread: SpaceChild RESET now passes the thread prefs so muted-thread
  subtraction survives space-child state changes.

Reviewer also verified: badge subtraction math exact (no double-subtraction),
encrypted thread replies caught by the timeline guard (m.relates_to is
cleartext), fresh prefs flow to handlers, single-owner wiring load-bearing.
Documented-acceptable: hasCurrentUserParticipated can lag until the server
bundle refreshes after your first reply; dedupe maps grow per-session only.

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

src/app/pages/client/ClientNonUIFeatures.tsx

@@ -6,6 +6,7 @@ import {
   Room,
   RoomEvent,
   RoomEventHandlerMap,
+  Thread,
   ThreadEvent,
 } from 'matrix-js-sdk';
 import { focusAssistActiveAtom } from '../../state/focusAssist';
@@ -446,8 +447,10 @@ function MessageNotifications() {
     };
   }, [mx, notificationSelected, selectedRoomId, deliverNotification]);
 
-  const handleNewReply = useCallback<RoomEventHandlerMap[ThreadEvent.NewReply]>(
-    (thread, mEvent) => {
+  const handleNewReply = useCallback(
+    // useRoomsListener prepends the emitting Room; the thread's own room lookup
+    // below is kept as the authority (identical object in practice).
+    (_room: Room, thread: Thread, mEvent: MatrixEvent) => {
       if (mx.getSyncState() !== 'SYNCING') return;
       const room = mx.getRoom(thread.roomId);
       if (!room || room.isSpaceRoom()) return;
@@ -457,8 +460,7 @@ function MessageNotifications() {
       // Suppress when the user is actively looking at this thread (or the inbox).
       if (
         document.hasFocus() &&
-        (notificationSelected ||
-          (selectedRoomId === thread.roomId && activeThreadId === thread.id))
+        (notificationSelected || (selectedRoomId === thread.roomId && activeThreadId === thread.id))
       ) {
         return;
       }