feat: 添加 Laravel Reverb 支持，更新 .env.example 文件以配置 WebSocket，增强彩票调度功能，更新 API 路由以支持期号管理与结果发布

app/Events/DrawCountdownBroadcast.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace App\Events;
+
+use Illuminate\Broadcasting\Channel;
+use Illuminate\Broadcasting\InteractsWithSockets;
+use Illuminate\Contracts\Broadcasting\ShouldBroadcastNow;
+use Illuminate\Foundation\Events\Dispatchable;
+use Illuminate\Queue\SerializesModels;
+
+/** 界面文档 §2.1：`draw.countdown` */
+class DrawCountdownBroadcast implements ShouldBroadcastNow
+{
+    use Dispatchable, InteractsWithSockets, SerializesModels;
+
+    /**
+     * @param  array<string, mixed>|null  $data  与 GET draw/current 的 data 相同
+     */
+    public function __construct(
+        public readonly ?array $data,
+        public readonly int $emittedAtMs,
+    ) {}
+
+    /** @return array<int, Channel> */
+    public function broadcastOn(): array
+    {
+        return [new Channel('lottery-hall')];
+    }
+
+    public function broadcastAs(): string
+    {
+        return 'draw.countdown';
+    }
+
+    /** @return array{data: array<string, mixed>|null, emitted_at_ms: int} */
+    public function broadcastWith(): array
+    {
+        return [
+            'data' => $this->data,
+            'emitted_at_ms' => $this->emittedAtMs,
+        ];
+    }
+}