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

app/Models/RadioAutoDjTrack.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * @method static \Illuminate\Database\Eloquent\Builder<static>|RadioAutoDjTrack where($column, $operator = null, $value = null)
+ * @method static \Illuminate\Database\Eloquent\Builder<static>|RadioAutoDjTrack create($attributes = [])
+ * @method static \Illuminate\Database\Eloquent\Builder<static>|RadioAutoDjTrack active()
+ * @method static \Illuminate\Database\Eloquent\Builder<static>|RadioAutoDjTrack orderBy($column, $direction = 'asc')
+ *
+ * @property string $title
+ * @property string|null $artist
+ * @property string|null $album
+ * @property string|null $artwork_url
+ * @property int|null $duration
+ * @property int $play_count
+ * @property \Carbon\Carbon|null $last_played_at
+ * @property bool $is_active
+ * @property int $sort_order
+ */
+class RadioAutoDjTrack extends Model
+{
+    #[\Override]
+    protected $table = 'radio_auto_dj_playlist';
+
+    #[\Override]
+    protected $guarded = ['id', 'created_at', 'updated_at'];
+
+    #[\Override]
+    protected $casts = [
+        'duration' => 'integer',
+        'play_count' => 'integer',
+        'last_played_at' => 'datetime',
+        'is_active' => 'boolean',
+        'sort_order' => 'integer',
+    ];
+
+    public function scopeActive($query)
+    {
+        return $query->where('is_active', true);
+    }
+
+    public function scopeOrdered($query)
+    {
+        return $query->orderBy('sort_order')->orderBy('title');
+    }
+
+    public function markPlayed(): void
+    {
+        $this->increment('play_count');
+        $this->update(['last_played_at' => now()]);
+    }
+
+    public static function getNextTrack(): ?self
+    {
+        $last = self::active()->orderBy('last_played_at', 'asc')->orderBy('sort_order')->first();
+
+        if ($last) {
+            return $last;
+        }
+
+        return self::active()->ordered()->first();
+    }
+}