Fix PHP 8 router parameter dispatching and lesson slug playback lookup

backend/app/Core/Request.php

@@ -13,6 +13,7 @@ class Request
     private array $queryParams;
     private array $bodyParams;
     private array $headers;
+    private array $routeParams = [];
 
     // Explicit properties to store authentication details to avoid deprecation warnings in PHP 8.2+
     public ?int $user_id = null;
@@ -78,6 +79,21 @@ class Request
         $this->queryParams = $queryParams;
     }
 
+    public function setParams(array $params): void
+    {
+        $this->routeParams = $params;
+    }
+
+    public function getParams(): array
+    {
+        return $this->routeParams;
+    }
+
+    public function getParam(string $key, $default = null)
+    {
+        return $this->routeParams[$key] ?? $default;
+    }
+
     public function get(string $key, $default = null)
     {
         return $this->bodyParams[$key] ?? ($this->queryParams[$key] ?? $default);