fix(models): correct UserSetting import namespace and add test coverage

tests/Unit/Providers/HorizonServiceProviderTest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Tests\Unit\Providers;
+
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Gate;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+class HorizonServiceProviderTest extends TestCase
+{
+    use RefreshDatabase;
+
+    #[Test]
+    public function it_defines_view_horizon_gate(): void
+    {
+        $this->assertTrue(Gate::has('viewHorizon'));
+    }
+
+    #[Test]
+    public function it_denies_access_for_users_not_in_list(): void
+    {
+        $user = User::factory()->create();
+
+        $this->assertFalse(Gate::forUser($user)->allows('viewHorizon'));
+    }
+}