Added Backend Add code to WebUI.

src/API/Backends/Discover.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\API\Backends;
+
+use App\Backends\Plex\PlexClient;
+use App\Libs\Attributes\Route\Route;
+use App\Libs\DataUtil;
+use App\Libs\Exceptions\InvalidArgumentException;
+use App\Libs\HTTP_STATUS;
+use App\Libs\Traits\APITraits;
+use Psr\Http\Message\ResponseInterface as iResponse;
+use Psr\Http\Message\ServerRequestInterface as iRequest;
+use Symfony\Contracts\HttpClient\HttpClientInterface as iHttp;
+use Throwable;
+
+final class Discover
+{
+    use APITraits;
+
+    public function __construct(private readonly iHttp $http)
+    {
+    }
+
+    #[Route(['GET', 'POST'], Index::URL . '/discover/{type}[/]', name: 'backends.get.users')]
+    public function __invoke(iRequest $request, array $args = []): iResponse
+    {
+        if (null === ($type = ag($args, 'type'))) {
+            return api_error('Invalid value for type path parameter.', HTTP_STATUS::HTTP_BAD_REQUEST);
+        }
+
+        if ('plex' !== $type) {
+            return api_error('Discover only supported on plex.', HTTP_STATUS::HTTP_BAD_REQUEST);
+        }
+
+        try {
+            $client = $this->getBasicClient($type, DataUtil::fromRequest($request, true));
+            assert($client instanceof PlexClient);
+        } catch (InvalidArgumentException $e) {
+            return api_error($e->getMessage(), HTTP_STATUS::HTTP_BAD_REQUEST);
+        }
+
+        try {
+            $list = $client::discover($this->http, $client->getContext()->backendToken);
+            return api_response(HTTP_STATUS::HTTP_OK, ag($list, 'list', []));
+        } catch (Throwable $e) {
+            return api_error($e->getMessage(), HTTP_STATUS::HTTP_INTERNAL_SERVER_ERROR);
+        }
+    }
+}

src/API/System/Supported.php

@@ -17,6 +17,6 @@ final class Supported
     #[Get(self::URL . '[/]', name: 'system.supported')]
     public function __invoke(iRequest $request): iResponse
     {
-        return api_response(HTTP_STATUS::HTTP_OK, ['supported' => array_keys(Config::get('supported'))]);
+        return api_response(HTTP_STATUS::HTTP_OK, array_keys(Config::get('supported')));
     }
 }