feat(百家乐): AI小班长下注后在聊天室发送普通聊天消息

- 下注成功后调用 broadcastBetMessage() 向聊天室广播
- 消息格式：「🤖 AI分析 小班长投了 N 金币，压【大/小/豹子】，大家加油！🎲」
- 发送者 AI小班长，发送对象 大家，action=说（普通聊天）
- AI 预测时显示「🤖 AI分析」标签，本地兜底时显示「📊路单统计」

app/Jobs/AiBaccaratBetJob.php

@@ -17,12 +17,14 @@
 namespace App\Jobs;
 
 use App\Enums\CurrencySource;
+use App\Events\MessageSent;
 use App\Models\BaccaratBet;
 use App\Models\BaccaratRound;
 use App\Models\GameConfig;
 use App\Models\Sysparam;
 use App\Models\User;
 use App\Services\BaccaratPredictionService;
+use App\Services\ChatStateService;
 use App\Services\UserCurrencyService;
 use Illuminate\Bus\Queueable;
 use Illuminate\Contracts\Queue\ShouldQueue;
@@ -171,5 +173,51 @@ class AiBaccaratBetJob implements ShouldQueue
             // 广播各选项的最新押注人数（让前台看到 AI 下注的人数增长）
             event(new \App\Events\BaccaratPoolUpdated($round));
         });
+
+        // 下注成功后，在聊天室发送一条普通聊天消息告知大家
+        $this->broadcastBetMessage($user, $round->room_id ?? 1, $betType, $amount, $decisionSource);
+    }
+
+    /**
+     * 广播 AI小班长本次下注情况到聊天室
+     *
+     * 以普通聊天消息形式发送，发送对象为大家。
+     *
+     * @param  User  $user  AI小班长用户对象
+     * @param  int  $roomId  目标房间 ID
+     * @param  string  $betType  下注方向：big|small|triple
+     * @param  int  $amount  下注金额
+     * @param  string  $decisionSource  决策来源：ai | local
+     */
+    private function broadcastBetMessage(
+        User $user,
+        int $roomId,
+        string $betType,
+        int $amount,
+        string $decisionSource,
+    ): void {
+        $chatState = app(ChatStateService::class);
+
+        $labelMap = ['big' => '大【骰子点数 11~17】', 'small' => '小【骰子点数 4~10】', 'triple' => '豹子【三骰同点】'];
+        $betLabel = $labelMap[$betType] ?? $betType;
+        $sourceTag = $decisionSource === 'ai' ? '🤖 AI分析' : '📊路单统计';
+
+        $content = "{$sourceTag} 小班长投了 {$amount} 金币，压【{$betLabel}】，大家加油！🎲";
+
+        $msg = [
+            'id' => $chatState->nextMessageId($roomId),
+            'room_id' => $roomId,
+            'from_user' => $user->username,
+            'to_user' => '大家',
+            'content' => $content,
+            'is_secret' => false,
+            'font_color' => null,
+            'action' => '说',
+            'sent_at' => now()->toDateTimeString(),
+        ];
+
+        $chatState->pushMessage($roomId, $msg);
+        broadcast(new MessageSent($roomId, $msg));
+        SaveMessageJob::dispatch($msg);
     }
 }