feat(backend): supergroup read receipts are captured like basic groups

backend/src/userbot/handlers/raw/read_receipts.py

@@ -7,25 +7,35 @@ from userbot.modules.raw_json import raw_json
 from userbot.modules.read_receipts import repository
 from utils.events import notify_bg_event
 
-HANDLES = (raw.types.UpdateReadHistoryOutbox,)
+HANDLES = (raw.types.UpdateReadHistoryOutbox, raw.types.UpdateReadChannelOutbox)
+
+
+def _watermark(update: raw.base.Update) -> tuple[int, int] | None:
+    if isinstance(update, raw.types.UpdateReadHistoryOutbox):
+        return utils.get_peer_id(update.peer), update.max_id
+    if isinstance(update, raw.types.UpdateReadChannelOutbox):
+        peer = raw.types.PeerChannel(channel_id=update.channel_id)
+        return utils.get_peer_id(peer), update.max_id
+    return None
 
 
 async def handle(
     client: PyroClient, update: raw.base.Update, _users: dict, _chats: dict
 ) -> None:
     ctx = client.capture
-    if ctx is None or not isinstance(update, raw.types.UpdateReadHistoryOutbox):
+    watermark = _watermark(update)
+    if ctx is None or watermark is None:
         return
-    chat_id = utils.get_peer_id(update.peer)
+    chat_id, max_id = watermark
     await repository.insert_read(
         ctx.pool,
         ctx.account_id,
         chat_id,
         chat_id,
         datetime.now(UTC),
-        update.max_id,
+        max_id,
         raw_json(update),
     )
     await notify_bg_event(
-        ctx.pool, "receipt", ctx.account_id, chat_id=chat_id, message_id=update.max_id
+        ctx.pool, "receipt", ctx.account_id, chat_id=chat_id, message_id=max_id
     )