weirsoe-party-protocol/docs/ISSUE-300-SCOREBOARD-NEXT-ROUND-BOOTSTRAP-INVARIANT.md

Issue #300 — scoreboard -> next-round bootstrap invariant

Refs: #300, parent #287

Hardened invariant

POST /lobby/sessions/{code}/rounds/next now treats scoreboard -> next round as a deterministic backend-owned bootstrap boundary:

• stale pre-created RoundConfig / RoundQuestion rows for the next round are deleted before bootstrap
• dependent lies / guesses for that stale next-round question are cleared with it
• current_round increments exactly once when a fresh next-round question can be selected
• the response makes reset semantics explicit with:
  • round_bootstrap.active_submissions = { lies: 0, guesses: 0 }
  • round_question.answers = []
  • submission_progress = { lies_submitted: 0, guesses_submitted: 0, players_expected: N }
  • reveal = null
  • leaderboard = null

Regression coverage

Targeted Django tests lock:

1. scoreboard -> next-round bootstrap returns explicit reset semantics
2. stale future round artifacts are removed before the next round is exposed
3. two consecutive round bootstraps do not leak prior-round state into the next round