Backend/moderation: drop redundant Reference.is_deleted filters

Migration 0151 maps is_deleted=True to UMS visibility=hidden, so the
Reference.is_deleted == False filters in ListReferences and
get_num_references are now redundant. Drop them and rely on UMS
visibility instead.

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

Author: aapeliv

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

@@ -32,6 +32,8 @@
     MeetupStatus,
     Message,
     ModerationObjectType,
+    ModerationState,
+    ModerationVisibility,
     Notification,
     NotificationDeliveryType,
     ParkingDetails,
@@ -1014,8 +1016,9 @@ 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]:
     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))
-        .where(Reference.is_deleted == False)
         .join(User, User.id == Reference.from_user_id)
         .where(User.is_visible)
         .group_by(Reference.to_user_id)

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

@@ -179,8 +179,7 @@ def ListReferences(
 
         to_users = aliased(User)
         from_users = aliased(User)
-        statement = select(Reference).where(Reference.is_deleted == False)
-        statement = where_moderated_content_visible(statement, context, Reference, is_list_operation=True)
+        statement = where_moderated_content_visible(select(Reference), context, Reference, is_list_operation=True)
         if request.from_user_id:
             # join the to_users, because only interested if the recipient is visible
             statement = (