fix(lobby): avoid orphaned round configs on round start

lobby/views.py

@@ -528,23 +528,25 @@ def start_round(request: HttpRequest, code: str) -> JsonResponse:
                 status=400,
             )
 
-        round_config, created = RoundConfig.objects.get_or_create(
-            session=session,
-            number=session.current_round,
-            defaults={"category": category},
-        )
-        if not created:
+        if RoundConfig.objects.filter(session=session, number=session.current_round).exists():
             return api_error(
                 request,
                 code="round_already_configured",
                 status=409,
             )
 
+        round_config = RoundConfig(
+            session=session,
+            number=session.current_round,
+            category=category,
+        )
+
         try:
             round_question = _select_round_question(session, round_config)
         except ValueError as exc:
             return api_error(request, code=str(exc), status=400)
 
+        round_config.save()
         session.status = GameSession.Status.LIE
         session.save(update_fields=["status"])
 
@@ -1101,22 +1103,24 @@ def start_next_round(request: HttpRequest, code: str) -> JsonResponse:
         if previous_round_config is None:
             return api_error(request, code="round_config_missing", status=400)
 
-        locked_session.current_round += 1
-        next_round_config = RoundConfig.objects.create(
+        next_round_number = locked_session.current_round + 1
+        next_round_config = RoundConfig(
             session=locked_session,
-            number=locked_session.current_round,
+            number=next_round_number,
             category=previous_round_config.category,
             lie_seconds=previous_round_config.lie_seconds,
             guess_seconds=previous_round_config.guess_seconds,
             points_correct=previous_round_config.points_correct,
             points_bluff=previous_round_config.points_bluff,
         )
+        locked_session.current_round = next_round_number
 
         try:
             round_question = _select_round_question(locked_session, next_round_config)
         except ValueError as exc:
             return api_error(request, code=str(exc), status=400)
 
+        next_round_config.save()
         locked_session.status = GameSession.Status.LIE
         locked_session.save(update_fields=["current_round", "status"])