Add radio embed widget, SSE real-time, song history, moderation panel, and Auto DJ

- Embed widget: standalone iframe player with dark/light/transparent themes, copy-paste embed code admin page
- Real-time SSE: streaming now-playing/listeners/dj events, replaces polling in radio-player and embed
- Song history: auto-records song changes to radio_song_plays table, Filament resource to view
- DJ moderation: unified panel for shouts approval, song request queue, DJ applications
- Auto DJ: playlist management with round-robin playback when no DJ is live
- Refactored radio-player Alpine component to use EventSource API with auto-reconnect

resources/views/filament/pages/radio/auto-dj-playlist.blade.php

@@ -0,0 +1,31 @@
+<?php
+
+?>
+
+<x-filament-panels::page>
+    @php $autoDj = \Illuminate\Support\Facades\Cache::get('radio_auto_dj_active'); @endphp
+
+    @if($autoDj)
+        <div class="bg-success-50 dark:bg-success-950 border border-success-300 dark:border-success-700 rounded-lg p-4 mb-4">
+            <div class="flex items-center gap-2">
+                <x-filament::icon name="heroicon-o-play-circle" class="w-5 h-5 text-success-600 dark:text-success-400" />
+                <div>
+                    <strong class="text-success-700 dark:text-success-300">Auto DJ is actief</strong>
+                    <p class="text-sm text-success-600 dark:text-success-400">Speelt: {{ $autoDj['title'] ?? 'Onbekend' }}{{ $autoDj['artist'] ? ' - ' . $autoDj['artist'] : '' }}</p>
+                </div>
+            </div>
+        </div>
+    @else
+        <div class="bg-gray-50 dark:bg-gray-900 border border-gray-200 dark:border-gray-700 rounded-lg p-4 mb-4">
+            <div class="flex items-center gap-2">
+                <x-filament::icon name="heroicon-o-pause-circle" class="w-5 h-5 text-gray-400" />
+                <div>
+                    <strong class="text-gray-700 dark:text-gray-300">Auto DJ is niet actief</strong>
+                    <p class="text-sm text-gray-500 dark:text-gray-400">Auto DJ wordt geactiveerd wanneer er geen DJ live is en er tracks in de playlist staan.</p>
+                </div>
+            </div>
+        </div>
+    @endif
+
+    {{ $this->table }}
+</x-filament-panels::page>