feat(dashboard): add Roles CRUD with permission-based menu filtering

- Roles CRUD: List/Create/Update/Delete actions, controller, requests
- Roles Vue pages: Index, Create, Edit (Options API, DashboardLayout)
- SidebarNav: filter menu items by user permissions via Inertia shared data
- HandleInertiaRequests: share permissions and roles arrays to frontend
- HttpKernel: register dashboard.permission middleware alias
- SidebarNavItem: add shield-check icon mapping

app/Containers/Dashboard/Actions/Roles/CreateRoleAction.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Containers\Dashboard\Actions\Roles;
+
+use Spatie\Permission\Models\Role;
+
+class CreateRoleAction
+{
+    public function run(array $data): Role
+    {
+        $role = Role::create(['name' => $data['name']]);
+
+        if (!empty($data['permissions'])) {
+            $role->syncPermissions($data['permissions']);
+        }
+
+        return $role;
+    }
+}