feat: web, webhook and telegram channel drivers

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BCrwHHnGCB5XH968Nxokqw

core/app/Channels/WebChannel.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Channels;
+
+use App\Enums\Presence;
+use App\Models\Delivery;
+use App\Models\Event;
+use App\Models\User;
+use Illuminate\Support\Facades\Cache;
+
+/** Инбокс. Ничего не шлёт (страница и так показывает всё), но присутствие определяет. */
+final class WebChannel implements ChannelDriver
+{
+    public function presence(User $user, array $config): Presence
+    {
+        return Cache::has("heartbeat:{$user->id}") ? Presence::Present : Presence::Absent;
+    }
+
+    public function deliver(Event $event, User $user, array $config, Delivery $delivery): DeliveryOutcome
+    {
+        return DeliveryOutcome::ok();
+    }
+
+    public function onDone(Event $event, Delivery $delivery): void {}
+}