fix(gameplay): harden scoreboard to round bootstrap invariants (#300)

lobby/views.py

@@ -193,6 +193,16 @@ def _prepare_mixed_answers(round_question: RoundQuestion) -> list[str]:
 
 
 
+def _reset_round_question_bootstrap_state(round_question: RoundQuestion) -> RoundQuestion:
+    Guess.objects.filter(round_question=round_question).delete()
+    LieAnswer.objects.filter(round_question=round_question).delete()
+    if round_question.mixed_answers:
+        round_question.mixed_answers = []
+        round_question.save(update_fields=["mixed_answers"])
+    return round_question
+
+
+
 def _resolve_scores(session: GameSession, round_question: RoundQuestion, round_config: RoundConfig) -> tuple[list[ScoreEvent], list[dict]]:
     guesses = list(round_question.guesses.select_related("player"))
     if not guesses:
@@ -1116,7 +1126,9 @@ def start_next_round(request: HttpRequest, code: str) -> JsonResponse:
         locked_session.current_round = next_round_number
 
         try:
-            round_question = _select_round_question(locked_session, next_round_config)
+            round_question = _reset_round_question_bootstrap_state(
+                _select_round_question(locked_session, next_round_config)
+            )
         except ValueError as exc:
             return api_error(request, code=str(exc), status=400)