expose sets list endpoint

backend/app/Http/Controllers/SetController.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Set\Set;
+use App\Set\UseCases\ListSets\ListSets;
+use Illuminate\Http\JsonResponse;
+
+class SetController extends Controller
+{
+    public function __construct(
+        private ListSets $listSets,
+    ) {}
+
+    public function index(): JsonResponse
+    {
+        $sets = array_map(function (Set $set): array {
+            return [
+                'id' => $set->getId(),
+                'name' => $set->getName(),
+            ];
+        }, $this->listSets->execute());
+
+        return new JsonResponse(['sets' => $sets]);
+    }
+}

backend/app/Set/UseCases/ListSets/ListSets.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Set\UseCases\ListSets;
+
+use App\Set\Set;
+use App\Set\SetRepository;
+
+class ListSets
+{
+    public function __construct(
+        private SetRepository $setRepository,
+    ) {}
+
+    /**
+     * @return list<Set>
+     */
+    public function execute(): array
+    {
+        return $this->setRepository->all();
+    }
+}