Give CPUs distinct personalities built on different poker libraries

Each CPU now thinks with one of four engines, each backed by a different
published library (pinned versions):

- montecarlo (@pokertools/evaluator): the existing balanced Monte Carlo
  equity player, moved to server/bots/montecarlo.js.
- calculator (poker-calculations): the library's decideAction over the
  table state; push/fold below 12BB via its jam breakeven equity.
  Skipped automatically if the native addon cannot load.
- range (poker-utils): tight player; preflop by hand-strength percentile,
  postflop equity vs an estimated opponent range, bluffs only when
  alpha/bluffEV say they pay.
- madehand (pokersolver): loose, sticky player that only looks at the
  made hand and draws.

server/ai.js assigns a mix of engines per table (makeStyles), falls back
to the Monte Carlo engine on errors, and legalizes every decision.
The engine and its parameters stay server-side; players cannot tell
which library a CPU uses. Tests cover every engine and the no-leak rule.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/tables.js

@@ -30,7 +30,7 @@ class Table {
 
     // { token, name, stack, buyIns, sittingOut, left, bot, style }
     // left: ハンド中に退席した人。ハンドが終わるまで席を予約しておく
-    // bot : CPU プレイヤー（style は思考の性格）
+    // bot : CPU プレイヤー（style は思考の種類と性格。ブラウザには渡さない）
     this.seats = new Array(this.maxSeats).fill(null);
     this.botTurn = null; // { key, at }: CPU が行動する時刻
     if (this.mode === 'cpu') this.seatBots(opts.cpuCount);
@@ -58,6 +58,7 @@ class Table {
       const j = crypto.randomInt(i + 1);
       [names[i], names[j]] = [names[j], names[i]];
     }
+    const styles = ai.makeStyles(n); // 思考（使うライブラリ）はなるべくばらけさせる。画面には出さない
     for (let k = 0; k < n; k++) {
       this.seats[k + 1] = {
         token: crypto.randomBytes(16).toString('hex'), // ブラウザには渡さない
@@ -67,7 +68,7 @@ class Table {
         sittingOut: false,
         left: false,
         bot: true,
-        style: ai.randomStyle(),
+        style: styles[k],
       };
     }
   }