Backend/moderation: use UMS helper in get_num_references

Filter reference counts through where_moderated_content_visible instead
of checking ModerationState.visibility directly, matching ListReferences.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: aapeliv

app/backend/src/couchers/servicers/api.py

@@ -32,8 +32,6 @@
     MeetupStatus,
     Message,
     ModerationObjectType,
-    ModerationState,
-    ModerationVisibility,
     Notification,
     NotificationDeliveryType,
     ParkingDetails,
@@ -1013,12 +1011,12 @@ def response_rate_to_pb(response_rate: UserResponseRate | None) -> dict[str, goo
         }
 
 
-def get_num_references(session: Session, user_ids: Iterable[int]) -> dict[int, int]:
+def get_num_references(session: Session, context: CouchersContext, user_ids: Iterable[int]) -> dict[int, int]:
+    query = where_moderated_content_visible(
+        select(Reference.to_user_id, func.count(Reference.id)), context, Reference, is_list_operation=True
+    )
     query = (
-        select(Reference.to_user_id, func.count(Reference.id))
-        .join(ModerationState, ModerationState.id == Reference.moderation_state_id)
-        .where(ModerationState.visibility == ModerationVisibility.visible)
-        .where(Reference.to_user_id.in_(user_ids))
+        query.where(Reference.to_user_id.in_(user_ids))
         .join(User, User.id == Reference.from_user_id)
         .where(User.is_visible)
         .group_by(Reference.to_user_id)
@@ -1054,7 +1052,7 @@ def user_model_to_pb(
             f"Context user_id: {context.user_id}, db_user id: {db_user.id} (username: {db_user.username})"
         )
 
-    num_references = get_num_references(session, [db_user.id]).get(db_user.id, 0)
+    num_references = get_num_references(session, context, [db_user.id]).get(db_user.id, 0)
     lat, lng = db_user.coordinates
 
     pending_friend_request = None

app/backend/src/couchers/servicers/search.py

@@ -741,7 +741,7 @@ def UserSearchV2(
             ).all()
         }
 
-        ref_counts_by_user_id = get_num_references(session, user_ids_to_return)
+        ref_counts_by_user_id = get_num_references(session, context, user_ids_to_return)
 
         def _user_to_search_user(user_id: int) -> search_pb2.SearchUser:
             lite_user = LiteUser_by_id[user_id]