Standard-rules-only leaderboard with client unranked indicators

Only standard-rules games now count toward leaderboard stats. Games
with any house rule variant are marked "Unranked" in the active rules
bar, and a notice appears in the lobby when house rules are selected.
Also fixes game_logger duplicate options dicts (now uses dataclasses.asdict,
capturing all options including previously missing ones) and refactors
duplicated achievement-checking logic into shared helpers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/main.py

@@ -531,6 +531,7 @@ async def _process_stats_safe(room: Room):
             winner_id=winner_id,
             num_rounds=room.game.num_rounds,
             player_user_ids=player_user_ids,
+            game_options=room.game.options,
         )
         logger.debug(f"Stats processed for room {room.code}")
     except Exception as e: