fix(playlist,multiplayer): commit to refresh participated users

app/router/v2/room.py

@@ -158,6 +158,8 @@ async def create_room(
     user_id = current_user.id
     db_room = await create_playlist_room_from_api(db, room, user_id)
     await _participate_room(db_room.id, user_id, db_room, db, redis)
+    await db.commit()
+    await db.refresh(db_room)
     created_room = APICreatedRoom.model_validate(await RoomResp.from_db(db_room, db))
     created_room.error = ""
     return created_room
@@ -261,7 +263,8 @@ async def remove_user_from_room(
         ).first()
         if participated_user is not None:
             participated_user.left_at = datetime.now(UTC)
-        db_room.participant_count -= 1
+        if db_room.participant_count > 0:
+            db_room.participant_count -= 1
         await redis.publish("chat:room:left", f"{db_room.channel_id}:{user_id}")
         await db.commit()
         return None

app/signalr/hub/multiplayer.py

@@ -413,6 +413,7 @@ class MultiplayerHub(Hub[MultiplayerClientState]):
                     host_id=room.room.host.user_id,
                 )
             )
+            await session.commit()
 
     async def setting_changed(self, room: ServerMultiplayerRoom, beatmap_changed: bool):
         await self.change_db_settings(room)
@@ -925,7 +926,8 @@ class MultiplayerHub(Hub[MultiplayerClientState]):
                 db_room = await session.get(Room, room.room.room_id)
                 if db_room is None:
                     raise InvokeException("Room does not exist in database")
-                db_room.participant_count -= 1
+                if db_room.participant_count > 0:
+                    db_room.participant_count -= 1
 
         if len(room.room.users) == 0:
             await self.end_room(room)