Every round deals the roles again

Decision

Each new round shuffles the roles afresh, so the imposter is not stuck on one player.

Why

In 1.x the next round kept the same imposter. The owner reported it as a bug on 2026-09-27 and asked that the shuffle be checked before any release.

Impact

• deal in src/lib/deal.ts shuffles the roles on every call; online, the Cloud Function deals (v2-rebuild).
• A shuffle can still hand the same player the role twice in a row by chance. That is allowed; a fixed imposter is not.