feat(backend): feed items carry the message id even when the message row is gone

backend/src/utils/read/feed.py

@@ -183,6 +183,7 @@ async def _build_items(
                     kind=row["chat_kind"],
                     has_avatar=chat.has_avatar if chat else False,
                 ),
+                message_id=row["message_id"],
                 message=message,
                 sender_id=sender_id,
                 sender_name=names.get(sender_id) if sender_id is not None else None,

backend/src/utils/read/models.py

@@ -226,6 +226,7 @@ class FeedItem(BaseModel):
     since: datetime
     message_count: int
     chat: FeedChat
+    message_id: int
     message: MessageView | None
     sender_id: int | None
     sender_name: str | None