Add application API and OpenAPI docs

app/Actions/Projects/ListVisibleProjects.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace App\Actions\Projects;
+
+use App\Actions\Permissions\PermissionService;
+use App\Enums\Permission;
+use App\Models\Project;
+use App\Models\User;
+use Illuminate\Database\Eloquent\Collection;
+
+class ListVisibleProjects
+{
+    public function __construct(
+        private readonly PermissionService $permissionService,
+    ) {}
+
+    /**
+     * @return Collection<int, Project>
+     */
+    public function handle(User $user): Collection
+    {
+        $projectQuery = Project::query()
+            ->orderByDesc('id');
+
+        if ($this->permissionService->allows($user, Permission::GlobalAdmin)) {
+            return $projectQuery->get();
+        }
+
+        $viewableProjectIds = $this->permissionService->viewableProjectIds($user);
+
+        if ($viewableProjectIds === []) {
+            return new Collection;
+        }
+
+        return $projectQuery
+            ->whereIn('id', $viewableProjectIds)
+            ->get();
+    }
+}