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/Http/Kernel.php

@@ -7,6 +7,7 @@ namespace App\Http;
 use App\Http\Middleware\AdminSecurityMiddleware;
 use App\Http\Middleware\ApiResponseCache;
 use App\Http\Middleware\Authenticate;
+use App\Http\Middleware\RadioApiKey;
 use App\Http\Middleware\BannedMiddleware;
 use App\Http\Middleware\DDoSTrackingMiddleware;
 use App\Http\Middleware\EncryptCookies;
@@ -120,5 +121,6 @@ class Kernel extends HttpKernel
         'force.staff.2fa' => ForceStaffTwoFactorMiddleware::class,
         'ddos.track' => DDoSTrackingMiddleware::class,
         'admin.security' => AdminSecurityMiddleware::class,
+        'radio.api' => RadioApiKey::class,
     ];
 }