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;
+    }
+}

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

@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Containers\Dashboard\Actions\Roles;
+
+use Spatie\Permission\Models\Role;
+
+class DeleteRoleAction
+{
+    public function run(Role $role): void
+    {
+        $role->delete();
+    }
+}

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

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Containers\Dashboard\Actions\Roles;
+
+use Spatie\Permission\Models\Role;
+
+class ListRolesAction
+{
+    public function run(): array
+    {
+        $roles = Role::with('permissions')->orderBy('name')->get();
+
+        return [
+            'roles' => $roles,
+        ];
+    }
+}

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

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Containers\Dashboard\Actions\Roles;
+
+use Spatie\Permission\Models\Role;
+
+class UpdateRoleAction
+{
+    public function run(Role $role, array $data): Role
+    {
+        $role->update(['name' => $data['name']]);
+
+        $role->syncPermissions($data['permissions'] ?? []);
+
+        return $role;
+    }
+}