feat: distinct response message for already-cited words

[Copilot]

When a player submits a word already guessed earlier in the same round, the bot responds with a distinct message and the duplicate word is excluded from the leaderboard and overlay.

Changes

• game/state.py: Added already_cited: bool to GuessResult. submit_guess() checks whether the normalized word already exists in _history before appending. If the word was already cited, it is not appended to _history, preventing duplicates from appearing in top_guesses() and the overlay leaderboard.

• bot/bot.py: New branch in guess handler for the already_cited case:

  • With score: 'chien' has already been suggested (50% similarity).
  • Without score: 'chien' has already been suggested.
  • is_found still takes priority — winning guesses always show the win message.

• Tests: TestAlreadyCited (7 tests) in test_game_state.py covering first-guess, same/different user, normalisation, duplicate exclusion from history, and new-game reset. TestGameStateLeaderboard updated with a dedicated test verifying already-cited words are excluded from top_guesses(). Three new tests in test_commands.py covering bot responses for scored, unscored, and winning already-cited words.

# Example flow
gs.submit_guess("alice", "chien")  # → already_cited=False, appended to history
result = gs.submit_guess("bob", "chien")
result.already_cited  # → True, NOT appended to history
# bot sends: "'chien' has already been suggested (50% similarity)."
# "chien" appears only once in top_guesses() / overlay

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[FlorentPoinsaut]

@copilot Les mots dupliqués sont quand même ajoutés au TOP GUESSES de l'overlay alors qu'ils ne devraient pas y être ajoutés

[Copilot]

@copilot Les mots dupliqués sont quand même ajoutés au TOP GUESSES de l'overlay alors qu'ils ne devraient pas y être ajoutés

Corrigé dans le commit 51387a1. Les mots déjà cités ne sont plus ajoutés à _history, donc ils n'apparaissent plus dans top_guesses() ni dans l'overlay.