feat: 添加实时广播功能，支持风险预警、玩法切换和赔率更新，增强大厅公共频道的广播能力

app/Events/RiskWarningBroadcast.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace App\Events;
+
+use Illuminate\Broadcasting\Channel;
+use Illuminate\Queue\SerializesModels;
+use Illuminate\Foundation\Events\Dispatchable;
+use Illuminate\Broadcasting\InteractsWithSockets;
+use Illuminate\Contracts\Broadcasting\ShouldBroadcastNow;
+
+/**
+ * 界面文档 §2.1：`risk.warning` —— 号码赔付池占用超 80% 预警推送。
+ *
+ * 触发时机：某号码的风险池占用比例超过阈值（默认 80%）时。
+ * 前端处理：该号码的玩法格子显示预警样式（如黄色边框或图标）。
+ */
+final class RiskWarningBroadcast implements ShouldBroadcastNow
+{
+    use Dispatchable, InteractsWithSockets, SerializesModels;
+
+    /**
+     * @param  int  $drawId  期号 ID
+     * @param  string  $drawNo  期号编号
+     * @param  string  $normalizedNumber  标准化后的 4 位号码
+     * @param  float  $usageRatio  占用比例（0-1 之间，如 0.85 表示 85%）
+     * @param  int  $emittedAtMs  发送时间戳（毫秒）
+     */
+    public function __construct(
+        public readonly int $drawId,
+        public readonly string $drawNo,
+        public readonly string $normalizedNumber,
+        public readonly float $usageRatio,
+        public readonly int $emittedAtMs,
+    ) {}
+
+    /**
+     * 公共频道，所有在大厅的玩家都能收到。
+     *
+     * @return array<int, Channel>
+     */
+    public function broadcastOn(): array
+    {
+        return [new Channel('lottery-hall')];
+    }
+
+    public function broadcastAs(): string
+    {
+        return 'risk.warning';
+    }
+
+    /**
+     * @return array{draw_id: int, draw_no: string, normalized_number: string, usage_ratio: float, usage_percent: int, warning_threshold: float, emitted_at_ms: int}
+     */
+    public function broadcastWith(): array
+    {
+        return [
+            'draw_id' => $this->drawId,
+            'draw_no' => $this->drawNo,
+            'normalized_number' => $this->normalizedNumber,
+            'usage_ratio' => round($this->usageRatio, 4),
+            'usage_percent' => (int) round($this->usageRatio * 100),
+            'warning_threshold' => 0.8, // 80% 阈值
+            'emitted_at_ms' => $this->emittedAtMs,
+        ];
+    }
+}